Biostatistics

Question 1

Branch of statistics that summarizes information about a group based on the actual data collected

Answer 1

Descriptive

Question 2

Branch of statistics where conclusions are prepared based on the data collected, with predictions made that go beyond the sample analyzed but are generally related to different but related situations

Answer 2

Inferential

Question 3

number that describes the population

Answer 3

Parameter

Question 4

number that describes the sample

Answer 4

Statistic

Question 5

reflects reproducibility or true exactness

Answer 5

Precision

Question 6

reflects closeness to the true value

Answer 6

Accuracy

Question 7

characteristic that varies between different individuals (gender, blood type)

Answer 7

Between-subject variable

Question 8

characteristic of an individual that varies with time (blood pressure, heart rate)

Answer 8

Within-subject variable

Question 9

Data type involving separate, indivisible categories

Answer 9

Discrete

Question 10

Data type involving infinite number of possible values that fit between any two adjacent values

Answer 10

Continuous

Question 11

Scale of measurement: Names or classification data, no order, arbitrary labels

Answer 11

Nominal

Question 12

Scale of measurement: Ordered data, ranks
Groups in sequence (one is better than the other)
Comparative quality or rank order

Answer 12

Ordinal

Question 13

Scale of measurement: Ordered categories with all intervals equal
Categories are randomly assigned
Exact different among groups (how much better)
Quantitative, mean and standard deviation

Answer 13

Interval

Question 14

Scale of measurement: Ordered categories with a fixed absolute zero
Interval with TRUE zero (real difference)

Answer 14

Ratio

Question 15

Skew where left tail is longer; mass of the distribution is concentrated on the right of the curve

Answer 15

Negative skew

Question 16

Skew where right tail is longer; mass of the distribution is concentrated on the left of the curve

Answer 16

Positive skew

Question 17

Peak sharpness where there is a normal distribution

Answer 17

Mesokurtic

Question 18

Peak sharpness where peakedness is greater than normal distribution

Answer 18

Leptokurtic

Question 19

Peak sharpness where peakedness is less than normal distribution

Answer 19

Platykurtic

Question 20

Percentage of data points exist that within 1 standard deviation from the mean

Answer 20

68%

Question 21

Percentage of data points exist that within 2 standard deviations from the mean

Answer 21

95%

Question 22

Percentage of data points exist that within 3 standard deviations from the mean

Answer 22

99%

Question 23

How to calculate joint probability of two independent events

Answer 23

P1 x P2

Question 24

How to calculate joint probability of two mutually exclusive events

Answer 24

P1 + P2

Question 25

How to calculate joint probability of non-mutually exclusive events

Answer 25

(P1 + P2) - (P1 x P2)

Question 26

Do larger sample sizes have wider or narrower confidence intervals?

Answer 26

Narrower

Question 27

Z-score used for 90% confidence interval

Answer 27

1.645 ~ 1.5

Question 28

Z-score used for 95% confidence interval

Answer 28

1.96 ~ 2.0

Question 29

Z-score used for 99% confidence interval

Answer 29

2.576 ~ 2.5

Question 30

Equation to calculate confidence interval

Answer 30

Mean +/- Z * (stand. dev. / square root n)

Question 31

Equation for standard error of the mean

Answer 31

Standard deviation / square root of sample size

Question 32

Statistical test used on 2 interval groups (e.g. height and weight) to show a linear relationship

Answer 32

Pearson correlation

Question 33

Statistical test used on 2 nominal groups (e.g. single vs married)

Answer 33

Chi-squared

Question 34

Statistic test used for 1 interval and 1 nominal group (2 groups only) E.g. blood pressure by gender

Answer 34

t-test

Question 35

Statistic test used for 2 groups (1 interval and 1 nominal) that are linked data pairs E.g. blood pressure before and after NBME

Answer 35

Matched pairs t-test

Question 36

Statistical test used for 2 or more groups (at least 1 nominal and 1 interval) E.g. pain improvement by two drugs in two age groups

Answer 36

One-way ANOVA

Question 37

Statistical test used to 2 or more groups, 2 nominal variables E.g. blood pressure in men and women from US and Canada

Answer 37

Two-way ANOVA

Question 38

Type of error involving incorrect rejection of a true null hypothesis (false positive) Chance is alpha value (P value)

Answer 38

Type I error

Question 39

Chance of type I error is given by this

Answer 39

Alpha value (P value)

Question 40

Type of error involving incorrectly retain a null hypothesis (fail to reject) a false negative Probability is beta (1 - power)

Answer 40

Type II error

Question 41

Chance of type II error is given by this

Answer 41

Beta (= 1 - Power)

Question 42

likelihood a study will detect an effect then there is one to be detected

Answer 42

Statistical power

Question 43

Statistical power increases as this type of error decreases

Answer 43

Type II

Question 44

5 steps in evidence-based medicine

Answer 44

Ask, Acquire, Appraise, Apply, Audit

Question 45

PICO(T) is used for this step in evidence-based medicine

Answer 45

Ask: convert information need into an answerable clinical question

Question 46

In evidence-based medicine, P in PICO describes this

Answer 46

Problem or population (patient)

Question 47

In evidence-based medicine, I in PICO describes this

Answer 47

Intervention

Question 48

In evidence-based medicine, C in PICO describes this

Answer 48

Comparison

Question 49

In evidence-based medicine, O in PICO describes this

Answer 49

Outcome