《英國醫(yī)學(xué)會雜志》（BMJ）自2008年9月開始至2015年由兩位流行病與統(tǒng)計(jì)學(xué)專家不間斷地出了300多期statistical question系列。在這個(gè)系列中，兩位學(xué)者每次出一道統(tǒng)計(jì)學(xué)選擇題，進(jìn)行選擇并解釋。現(xiàn)在醫(yī)學(xué)論文與統(tǒng)計(jì)分析公眾號的鄭老師精選300道Statistical Question，請有興趣的朋友們進(jìn)行回答。我在其中進(jìn)行英文版的學(xué)習(xí)，加強(qiáng)統(tǒng)計(jì)學(xué)實(shí)踐知識和提高英語閱讀能力。

醫(yī)學(xué)四大期刊：lancet,nature,BMJ, NEJM

journal：[`d??nl]n.（專業(yè)性）日志，日報(bào)，雜志；分類賬。

【結(jié)構(gòu)分析】journal=journ（日，天）+al（形容詞后綴）→每日的→日志，日報(bào)，雜志。法語詞根journ-（天，日）來自古法語，由jo-和形容詞后綴-urn組成。

目錄：

2021年7月計(jì)劃0篇，7月實(shí)際4篇。

Question01-11: distribution

Question02-12: error

Question03- 07：the study design

Question04-15: probability

2021年8月計(jì)劃5篇；8月實(shí)際6篇。

Question05-16:measure of spread

Question 06-14:study design

Question 07-18：normally distributed

Question 08-20: normal distribution

Question 09-04: sample size

Question 10-21：statistical test

Question01-11: distribution

The average number of suicides reported each month in one county last year was 3.2. To compare numbers of suicides between months, calculating P values or confidence intervals, which probability distribution would be most appropriate to use?

Binomial

Normal

Poisson

Weibull

Answer：The Poisson distribution describes the occurrence of rare events happening at random in a large population, which fits the bill here. It is also necessary to check that there are not linkages between the suicides, or clustering, as this will affect the interpretation of the expected probabilities. the Poisson distribution is helpful for ‘back of the envelope’ calculations ，because when the number of events is reasonably large, the standard deviation of the distribution is the same number as the square root of the mean. (Technically the binomial distribution could be used but it requires long calculations of large numbers.)

suicide：[`su?sa?d] v.自殺n.自殺；自殺者。

【結(jié)構(gòu)分析】suicide=sui（自己）+cid（切割，殺）+e→自殺；拉丁詞根cid-/cis-（切，殺）；

Bill:=case

Linkages:鏈結(jié)，

Clustering:聚類，

Interpret： v. 解釋；口譯。 【結(jié)構(gòu)分析】interpret=inter（之間）+pret（交換）→在中間交換（信息）→解釋，口譯。

back of the envelope’ calculations：信封背后的計(jì)算。

Deviation：[`div?`e??n]n.偏差；誤差；背離。

【結(jié)構(gòu)分析】deviation=de（離開）+vi（道路）+ation（動(dòng)名詞后綴）→偏離。拉丁詞根vi-/via-（行走，道路）來自拉丁語名詞via（道路）。它和拉丁詞根vehi-/vect-（交通，運(yùn)輸）以及日耳曼單詞way（道路）最終都源自原始印歐語詞根*wegh-（交通，運(yùn)輸）。

需要去檢查自殺之間與聚類的關(guān)聯(lián)性，因?yàn)樗鼤绊憣︻A(yù)期概率的解釋。

這個(gè)分布的標(biāo)準(zhǔn)偏差和均值的平方根相同。(從技術(shù)上來講，二項(xiàng)分布可以被使用，但需要對大量數(shù)據(jù)進(jìn)行長時(shí)間計(jì)算)

2021年7月1日星期四

Question02-12: error（202107121周一）

In a trial of a herbal treatment for symptoms of menopause /the power calculation described in the protocol /required 400 patients to be randomised. Unfortunately, recruitment was slow and the trial had to be stopped after 200 patients as funding was running out. Which if any of the following statements is true?

a) The possibility of a type one error is increased and the possibility of a type two error is unaltered.

b) The possibility of a type two error is increased and the possibility of a type one error is unaltered.

c) The possibility of both a type one error and a type two error is increased.

d) The possibility of both types of error is unaltered.

Answer

A type one error occurs when a study indicates/ an effect or an association that does not exist, the so called “false positive result.” The rate of false positive results (we are prepared to accept as the price for scientific enquiry) is chosen /by the investigator or the reader and is referred /to as the level for statistical significance. Often this is set at 5% or one in 20. This kind of error has nothing to do with sample size.

A type two error occurs when a study fails to detect an effect or an association that does exist. For any given investigation, smaller studies have less ability to pick up an association or effect than do larger studies.

Small studies can be misleading in another way. As small studies are “imprecise” and have wide confidence intervals, it is only the ones with abnormally large effects that manage to achieve “statistical significance.” If the only studies conducted on, say, a new surgical technique are small, then by relying only on the “statistically significant” ones we are likely to overestimate the promise of the new treatment. So even though we might rely on the “significant” study to show that something is going on, it would be prudent to consider all the “non-significant” studies as well in estimating the likely size of the effect.

Herbal treatment:traditonal chinese medicine treatment。

menopause :=meno+pause(暫停、停止);the time during which a woman gradually stops menstruating, usually at around the age of 50.

Indicate:in(在里面)+dic（指示）+ate（V的后綴）=在里面指示=表明，指出，告知。

Detect=de（反義）+tect（遮蓋）→打開遮蓋→察覺，發(fā)現(xiàn)，探測。

precise：precise：[pr?`sa?s] adj.精確的；明確的。 【結(jié)構(gòu)分析】precise=pre（在前面）+cis（切割）+e→預(yù)先切割好的→精準(zhǔn)匹配好的→精確的，明確的。Im(不)。

The rate of false positive results （we are prepared to accept ）as the price for scientific enquiry is chosen /by the investigator or the reader and is referred /to as the level for statistical significance.

長難句翻譯1：我們正準(zhǔn)備接受假陽性結(jié)果作為科學(xué)要求價(jià)格接近于，通過研究者或者讀者和統(tǒng)計(jì)學(xué)意義水平的參考。

正確翻譯：我們準(zhǔn)備接受的假陽性結(jié)果率作為科學(xué)調(diào)查的價(jià)格是由研究者或讀者選擇的，并被稱為統(tǒng)計(jì)顯著性水平。

主要錯(cuò)誤點(diǎn)：chosen是選擇，而不是接近，接近是close。

長難句翻譯2：小研究能力小于大研究。

it is only the ones with abnormally large effects that manage to achieve “statistical significance.”

長難句翻譯3：它僅僅是在正常大影響下成功的實(shí)現(xiàn)統(tǒng)計(jì)學(xué)意義。

正確翻譯：因此只有具有異常大影響的研究才能實(shí)現(xiàn)“統(tǒng)計(jì)意義”

主要錯(cuò)誤點(diǎn)：ab前綴是相反的意思，改變了原來單詞意思。

If the only studies conducted on, say, a new surgical technique are small, then by relying only on the “statistically significant” ones we are likely to overestimate the promise of the new treatment。

長難句翻譯4：如果只有研究被執(zhí)行，說，一個(gè)新的外科手術(shù)技術(shù)是小的，然后僅僅依靠 “統(tǒng)計(jì)學(xué)意義”，我們很可能過度估計(jì)新治療的效果。

正確翻譯：比如對一種新的外科手術(shù)技術(shù)進(jìn)行的研究樣本量很小，那么僅依靠“具有統(tǒng)計(jì)學(xué)意義”的研究，我們可能會高估新療法的前景。

主要錯(cuò)誤點(diǎn)：promise，有前景的，promise=pro（在前面，提前）+mis（放出）+e→提前放出的東西→許諾，希望

So even though we might rely on the “significant” study to show that something is going on ，it would be prudent to consider all the “non-significant” studies as well in estimating the likely size of the effect.

長難句翻譯5：因此即使我們可能依靠有“統(tǒng)計(jì)意義”的研究去展示某些事正在發(fā)生，它可能什么去思考所有“無意義”研究和估計(jì)可能的影響的大小。

正確翻譯：因此，即使我們可能依靠“統(tǒng)計(jì)學(xué)意義”研究來表明正在發(fā)生某些事情，但在估計(jì)影響的可能大小時(shí)也應(yīng)預(yù)先考慮所有“沒有統(tǒng)計(jì)學(xué)意義”研究。

主要錯(cuò)誤點(diǎn)：size本意是大小，不只有樣本量的含義。prudent：[`pr?dnt]adj.謹(jǐn)慎的；精明的；節(jié)儉的。

【結(jié)構(gòu)分析】prudent=pr(o)（提前）+ud（=vid，看）+ent（形容詞后綴）→有遠(yuǎn)見的，未雨綢繆的→謹(jǐn)慎的，精明的，節(jié)儉的。

2021年7月12日星期一

Question03- 07：the study design（20210716周五）

A group of investigators decided to test the hypothesis that using post menopausal hormones increases the risk of breast cancer. They identified 500 women with newly diagnosed breast cancer, and 500 women of the same age, from the same neighbourhoods as the first group of women, who did not have breast cancer. Then they asked all women about their past use of postmenopausal hormones.

What answer best describes the study design used here?

a) A retrospective cohort study

b) An incidence study

c) A case crossover study

d) A case-control study

Answer

d—

Case-control studies gather participants together on the basis of whether they are cases with disease or controls free from disease. The question is then asked “What have these people done in the past that may have led to disease?”

Retrospective cohorts by contrast follow up a group of people who have already been gathered together for some reason in the past (perhaps they attended the same school or were born in the same maternity unit). The question is then asked “What has happened to these people now?” Cohort studies may of course measure incidence.

A case crossover study is a special example of a case-control study/ where all people are cases /though the timing and degree of exposure to risk factors may vary.

hypothesis：[ha?`pɑθ?s?s]n.假設(shè)。

【結(jié)構(gòu)分析】hypothesis=hypo（在下面）+thes（擺放）+sis（名詞后綴）→擺放在下面，作為論證基礎(chǔ)的東西→假設(shè)

an idea or explanation of something that is based on a few known facts but that has not yet been proved to be true or correct. [Oxford definition]

hormones：

breast:either of the two round soft parts at the front of a woman’s body that produce milk when she has had a baby. [Oxford definition]

2021年7月16日（星期五）

Question04-15: probability（20210720周二）

Mike has only two children, and they are called Pat and Alex, which could equally be boys’ or girls’ names. In fact, Pat is a girl.What is the probability that Alex is a boy?

a) 50%

b)Slightly less than 50%

c)Slightly more than 50%

d)Between 60% and 70%

e)Between 40% and 30%

Answer

Although this could be about the relative popularity of ambiguous names for boys and girls or about subtle imbalances in the sex ratio, it is not meant to be. The clue to the correct answer is in thinking about what we do not know about the family and what we do know already, and applying this to the expected probabilities of girls and boys.

We do not know if Pat was born first or second. We do know that there are only two children and that Pat is a girl. I am assuming that in the population, 50% of children are girls.

The birth order and relative frequency of two child families are: boy, boy (25%), girl, girl (25%), boy, girl (25%) girl, boy (25%). We know Mike’s family does not have two boys, since Pat is a girl, so we are only left with three choices for families with at least one girl. Two of these pairs have a boy and one does not. Hence the probability that Alex is a boy is two thirds or 66.7%.

If we had been told that Pat was born first then the probability that Alex is a boy drops to 50%.

This is initially surprising but illustrates that applying what we know already makes a difference to the meaning of a simple statistic such as “fifty percent of children are girls.” The formal study of conditional probabilities such as these is covered by Bayesian statistics.

翻譯與理解：

Although this could be about the relative popularity of ambiguous names for boys and girls or about subtle imbalances in the sex ratio,it is not meant to be。

我的：雖然這可能是關(guān)于男孩和女孩不同名字的相關(guān)概率，或者是性別比例的什么不平衡，它并不意味著是；

翻譯難點(diǎn)：

ambiguous不認(rèn)識，根據(jù)認(rèn)識的單次猜測很可能是差異的、不同的。正確的是模棱兩可的。

Subtle：不認(rèn)識，無法猜測。=slight

Imbalances：主要是前綴im的意思不確定。Impossible,否定前綴。我太厲害了，完全正確。

Clue：線索；提示。 【詞源解釋】來自古英語，本意是“線團(tuán)”。在古希臘神話中，雅典王子忒修斯作為貢品前往克里特島，殺死了迷宮里面的人首牛身怪米諾陶洛斯，憑借線團(tuán)留下的線索逃出迷宮

Google翻譯：雖然這可能是與男孩女孩流行相關(guān)的模糊名字，或者是性別比例微妙的不平衡，但并不意味著就是。

Question05-16:measure of spread(20210802周一)

Which, if any, of the following are measures of spread?

a) Mode

b) Interquartile range

c) Skewness

d) Variance

Answer

When presenting numerical data it is useful to give an idea of the range of values covered by the data. The maximum and minimum values would define the entire range, but would not describe how typical these values would be. Measures of spread provide a summary of how spread out observations typically are.

The interquartile range is described by the bottom and top values that contain the middle 50% of the observations in the set of data. 25% of observations fallbelow this range and 25% above it.

Variance is the average of the square of all the differences between individual observations and the mean. Taking the square root of this gives the familiar standard deviation.

The mode is the most frequent value in a set of data and does not measure spread.

Skewness is a measure of the lack of symmetry in a set of data and does not measure spread.

Spread:傳播，分布。

Mode:眾數(shù)

Interquartial:四分位數(shù)

presenting numerical data：數(shù)字?jǐn)?shù)據(jù)；

bottom:min；bo掉到了托鵝門的最底部。

fallbelow=fall+be+low

symmetry：[`s?m?tri] n.對稱；對稱性；勻稱；整齊。 【結(jié)構(gòu)分析】symmetry=sym（一起）+metr（尺度）+y（名詞后綴）→擁有相同的尺度→對稱。 希臘詞根metr-/meter-（米，測量，尺度，比例，韻律）來自希臘語名詞metron（測量，尺度，比例，韻律）。

symptom：[`s?mpt?m] n.癥狀；征兆。 【結(jié)構(gòu)分析】symptom=sym（一起）+pto（落下，發(fā)生）+m（名詞后綴）→一起發(fā)生的事情→癥狀。

Measures of spread provide a summary of how spread out observations typically are.

翻譯：分布的測量提供了觀察通常是如何（向外分布）分散的（總和）概括。

Variance is the average of the square of all the differences between individual observations and the mean.

方差是單獨(dú)的觀測與均值之差的平方的平均數(shù)，

Taking the square root of this gives the familiar standard deviation.

這些平方根給與統(tǒng)一的標(biāo)準(zhǔn)（劃分）偏差。

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 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? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Question 06-14:study design(20210809周一)

A neurologist wanted to study the risk of stroke and transient ischaemic attack in people with a diagnosis of migraine. From her headache clinic she selected cases of migraine and controls without migraine.She collected stroke and transient ischaemic attack outcomes by writing to all subjects and their general practitioners five years later. Which study design best describes what was done?

a) Ecological study

b) Cohort study

c) Clinical trial

d) Case-control study

Answer

The case control design looks at the end of a disease or process. Patients are recruited into the study in two groups. One group, the cases, has already had an outcome and the other group, the controls, has not. The question is then posed as to what these two groups of people did in the past.

Despite the word in this study “cases” of migraine and “controls” without migraine are in fact the beginning of a study looking forward over time to the final outcome of stroke or transient ischaemic attack. This makes the study a cohort study. Migraine is examined as a potential risk factor. In this study migraine is not the outcome but the exposure.

An ecological study might compare hospital stroke admissions data with prescriptions of migraine medication /on a county by county basis throughout the United Kingdom.

A clinical trial is an experiment. The clinical investigator decides what intervention each person will receive and then follows each person over time to observe the effects. As described, the above study does not involve any such intervention.

一個(gè)神經(jīng)科醫(yī)生想要研究在診斷為偏頭痛患者中關(guān)于中風(fēng)和transient ischaemic發(fā)作風(fēng)險(xiǎn)。從她的頭痛診所挑選出偏頭案例和非偏頭痛案例作為對照。5年以后通過寫信給所有的受試者和全科醫(yī)生來收集中風(fēng)和transient ischaemic發(fā)作的結(jié)果。這屬于哪種研究類型？生態(tài)研究，隊(duì)列研究，臨床研究，病例對照研究。

答案分析：這病例對照設(shè)計(jì)一般在疾病結(jié)束或者過程中。病人被安排進(jìn)入兩個(gè)組，一個(gè)組是病例組，已經(jīng)有結(jié)局；另一個(gè)組是對照組，沒有結(jié)局。然后這個(gè)問題被設(shè)置：兩組人過去做了什么。

（我的理解：病例對照研究，與未患該病的人對照尋找過去是什么導(dǎo)致了患病，觀察性研究）

由于在研究中偏頭痛“案例”和沒有偏頭痛的“對照”這些單詞是（結(jié)束時(shí)間對于中風(fēng)或transient ischaemic發(fā)作最終結(jié)局）研究的開始， 所以這是一個(gè)隊(duì)列研究。偏頭痛被審視為一項(xiàng)潛在危險(xiǎn)因素，在這項(xiàng)研究中偏頭痛不是結(jié)局而是暴露。（觀察性研究）

一項(xiàng)生態(tài)性研究會在整個(gè)英國以縣為單位，比較醫(yī)院中風(fēng)入院數(shù)據(jù)和偏頭痛藥物處方。（這里學(xué)習(xí)了with的兩種用法，一是表并列，并列有兩種，成分并列，和句子并列；二是表伴隨）

臨床試驗(yàn)是一種試驗(yàn)。臨床研究者決定每個(gè)人接受哪種干預(yù)，然后在結(jié)束時(shí)間跟蹤每一個(gè)人去觀察這個(gè)影響。正如描述，這項(xiàng)研究沒有設(shè)計(jì)任何干預(yù)。（干預(yù)性研究）

詞匯積累：

Stroke;中風(fēng)

transient ischaemic attack：短暫性腦缺血發(fā)作

their general practitioners：全科實(shí)踐者，全科醫(yī)生

intervention干預(yù)

prescriptions處方

county縣級

1.Despite the word（ in this study “cases” of migraine and “controls” without migraine ）are in fact the beginning of a study（ looking forward over time to the final outcome of stroke or transient ischaemic attack）.

長難句的理解：找出簡單句。Word is beginning.

主要在于后半截理解：beginning，study look time to outcome.

我的直譯：案例和對照這些詞是一個(gè)（為了尋找時(shí)間結(jié)束時(shí)中風(fēng)或短暫性缺血發(fā)作的結(jié)局）研究的開始

公眾號給出的翻譯：盡管本研究中的措詞是偏頭痛的“病例組”和不是偏頭痛的“對照組”，但實(shí)際上是一項(xiàng)研究的開始，隨著時(shí)間的流逝，我們期待中風(fēng)或短暫性腦缺血發(fā)作的作為最終結(jié)果。

公眾號的翻譯我閱讀會存在很多疑惑。

Question 07-18：normally distributed（20210816周一）

Question

If a statistician tells you that your data are not normally distributed and the distribution has “fat tails,” which if any of the following will be true?

a) Extreme values may be more frequent than in a normal distribution1

b) 95% confidence intervals can not be computed

c) Parametric statistics can not be used

d) 95% confidence intervals will be narrower than those suggested by a normal distribution.

Answer

The tails of a distribution are the regions furthest from the middle or main body of the distribution. Many things measured in medicine do look like normal distributions, but not all of them do. When extreme values happen more often than expected in a normal distribution this is described as a distribution with fat tails. As more observations lie outside the 95% confidence limits of a normal distribution2, the true 95% confidence interval for a fat tailed distribution will be wider than expected on the basis of a normal distribution.

The distribution of stock market values has distinctly fat tails. More large falls and gains/ occur /than expected. In general, when multiple correlated factors/ influence/ an outcome then extreme values are more likely to occur.Cardiovascular risk can follow this pattern.

Lack of conformity to a normal distribution does not mean one has to immediately give up all hope of using parametric statistics. A transformation using logarithms, square root or other suitable procedure may produce a normal fit. Cardiovascular risk is not always normally distributed and the Framingham model uses a different statistical parameter (the Weibull distribution) as the basis for its predictions. So long as a suitable statistical distribution can befound, 95% confidence intervals may still be computed.

積累詞匯：

1.Extreme values，極致值

2.Parametric，參數(shù)

3.the regions furthest，最遠(yuǎn)的區(qū)域

4.stock market values，股票市場價(jià)值

5.distinctly，明顯的

6. Cardiovascular risk心血管風(fēng)險(xiǎn)

7. pattern模式

8.Lack of conformity，一致性，聯(lián)合，統(tǒng)一

9. Framingham model弗雷明翰心血管風(fēng)險(xiǎn)模型

10. computed，計(jì)算機(jī)和計(jì)算

翻譯：

1. 極致值的出現(xiàn)可能比正態(tài)分布更加頻繁

什么是extreme valve?

為什么extreme valve of not normally distributed比normally distibuted更加頻繁？

2.正如很多觀察者，（躺在）95%的置信下限的外部

當(dāng)更多的觀測值超出正態(tài)分布的95%置信限時(shí)

lie躺;? 平躺;? 平臥;? 平放;? 處于，保留，保持(某種狀態(tài)); n. 謊言;? 位置;? AS翻譯有誤，應(yīng)該為“當(dāng)”。

Question 08-20: normal distribution(20210817周二)

Which, if any, are true of a normal distribution?

a) It is symmetrical

b) The mean is equal to the median

c) The mean is equal to the mode

d) The skewness is positive

Answer

The normal distribution is the familiar bell shaped curve and is symmetrical in reflection about the mid-value. Because every point on one side of the curve is matched by a corresponding value on the other side,the mean occurs at the same place on the curve as the middle value, or median.Furthermore, the middle value is also the most frequent value or mode.

Skewness describes the degree to which a distribution is not symmetrical, so the normal distribution is not skewed.

詞匯積累

Symmetrical，Sym+meter

Mode，眾數(shù)

Skew,斜度

Bell，鐘

Question 09-04: sample size (20210817周二)

Which of the following will affect the sample size calculation for a clinical trial? (There may be more than one correct statement.)

a) Power

b) Significance level

c) Size of effect to detect

d) Variability of primary outcome

Answer：

These are the four pieces of information required for a sample size calculation.

Larger sample sizes will result in increased power.

Formal“significance” may be set at any P value1. The smaller the P value chosen as indicating significance /the larger will be the required /sample size8.

Large clinical differences/ are easier to detect/ that small ones. The smaller the clinical effect that it is desired to detect, the larger will be the required sample size2.

If the outcome (measure) is highly variable /this will act like “noise,” making it difficult to detect the “signal” of the clinical effect3 .Variability in a continuous measure may be assessed by the standard deviation4. The larger this is, the larger will be the required sample size to detect a certain clinical effect5. Trials are sometimes designed to reduce variability by using strictin clusion criteria to ensure that people in the trial are more similar (for example, similar stage of illness, similar age, similar ethnicity)6. This will reduce the required sample size at the expense of reducing wider generalis ability7.

Vocabulary accumulation

detect,un+cover

significance,檢驗(yàn)水準(zhǔn)

translate

正式的“檢驗(yàn)水準(zhǔn)“會可以被設(shè)置為任意P值。

Size of effect指的是效應(yīng)值,渴望被發(fā)現(xiàn)的臨床效果越小，所需樣本量就越大。

如果測量的結(jié)局有很高的差異性，這就像噪音一樣起作用，去發(fā)現(xiàn)臨床效果的“信號”就更加困難。

連續(xù)性變量的差異程度可以通過標(biāo)準(zhǔn)差來評估。

為了發(fā)現(xiàn)確定的臨床效應(yīng)量被要求更大的樣本量。

試驗(yàn)被設(shè)計(jì)通過嚴(yán)格的入排標(biāo)準(zhǔn)確保參與試驗(yàn)的人的更加相似，來減少差異性（例如，相同的疾病情況，相同的年齡，相同的名族）。

減少更寬泛的能力的消費(fèi)，這里減少了對樣本量的要求。

作為檢驗(yàn)水準(zhǔn)指標(biāo)的P值越小，所需樣本量越大。

總結(jié)：power、p、different、effect、variable與n的關(guān)系。

How to reduce the variability?strictin clusion criteria

認(rèn)識的名詞：

power,significance,p,clinical different,clinical effect,varibility,standrard deviation；

疑問：

1.what is effect?

The different of mean or rate,ratio

2.what is varibility primary outcome?

比如研究某藥物治療高血壓的主要結(jié)局是“有效率”，20-30歲有效率是30%，30-40歲有效率是25%，40-50歲有效率是20%；不同年齡之間的主要結(jié)局的差異程度；

Question 10-21：statistical test（2021/8/23 周一）

Which of the following statistical tests would be your first choice in each of the studies below?

Test:

1 χ2 for contingency tables? 卡方列聯(lián)表

2 Two sample t test

3 Log rank test

4 Poisson test

5 Pearson’s correlation coefficient

6 Paired t test

Study:

a) The occurrence of heart attacks on duty in the staff of two airlines

b) Change in uric acid concentrations in people with gout before and after starting a new diet

c) Cholesterol concentrations in people from high and low income households in a health survey

d) The association of car colour with owner’s personality type

Answer

a) Poisson distribution based test

b) Paired t test

c) Two sample t test

d) χ2 test

Heart attacks are likely to be a rare occurrence in airline staff on duty and to occur in a large pool of susceptible people. The Poisson distribution models this type of study well.

Uric acid can be measured on a continuous scale and follows a fairly symmetrical distribution. If concentrations are measured in each person before and after starting a diet,then the two measurements are paired within individuals and their difference will probably follow a normal distribution. The paired t test fits the bill.

Cholesterol concentrations in people from households with high and low incomes in a health survey/ can also be measured on a continuous scale. However, the people with a high or a low income are different and cannot be paired, so a two sample t test is appropriate. The test works best if the cholesterol concentration is normally distributed, which is the case in most populations.

Car colour falls into categories with no particular value or order and the same is true of personality type. χ2 tests may be used to assess associations between categorical variables. This could be done for all colours and all personality types in one table to produce a global assessment of “something is going on,” or this could be done for one colour and one personality type at a time by splitting the data into two categories, such as “red and not red”“extrovert and not extrovert.”

χ2 for contingency tables （chi-square test）列聯(lián)表

what is poisson test?為什么我腦子里面的一點(diǎn)關(guān)于泊松分布的記憶都搜索不出來，只是有印象學(xué)過這個(gè)名詞。

What is χ2 test?

What is t test?

What is poisson test?

一段時(shí)間內(nèi)，拋n次硬幣，求幾次硬幣向上的概率。

1.Duty,責(zé)任，值班。

2.Uric，尿的；杯子里面的小草被蠟燭燒起來，月亮看見有人撒了一泡尿，把火滅了。

3.Acid，酸（n，adj），sour（adj）；The concentration of acid，啊的一聲，實(shí)驗(yàn)室發(fā)生了硫酸撒到皮膚的事故；

4.Gout，痛風(fēng)，noun[U] 準(zhǔn)備出去，突然頭痛發(fā)作了。

a disease that causes painful swelling in the joints, especially of the toes, knees and fingers。

5.Cholesterol，膽固醇，chol（膽囊）+e+ster（固化）+ol; [k??lest?r??l]

a substance found in blood, fat and most tissues of the body. Too much cholesterol can cause heart disease.

記憶法：月亮形狀的椅子看見巨型雞蛋就木棍敲碎了，嚇破了膽，死特凝固看著雞蛋和木棍。

6.within=with+in,在什么里面

7.pair，two things the same。

7.1 susceptible,易感人群

8. bill，賬單，提議；

9.category,類別，種類

10. split，分開，分離，分類

11.extrovert，內(nèi)向；extro+over 向外翻轉(zhuǎn)

這兩個(gè)測量值在個(gè)體內(nèi)是配對的。

我的翻譯：在一個(gè)表中所有的顏色和個(gè)性進(jìn)行處理，為了產(chǎn)生“某事正在進(jìn)行”的全球評估，在一個(gè)時(shí)間內(nèi)一個(gè)顏色和一個(gè)個(gè)性通過分配這個(gè)數(shù)據(jù)進(jìn)入兩分類，進(jìn)行處理。

作者翻譯：可以針對一張表中的所有顏色和所有個(gè)性類型進(jìn)行此操作，以對“某事正在發(fā)生”進(jìn)行全局評估，也可以通過將數(shù)據(jù)分為兩類，一次針對一種顏色和一種個(gè)性類型進(jìn)行此操作，例如“紅色和非紅色”，“性格外向和非外向

global assessment翻譯錯(cuò)誤，全球就是全方位，全面的評估。