Biostats 5

Question 1

What type of graph is used to represent a chi squared test

Answer 1

bar graph; no whisker

no variance or distribution

Question 2

What is the use of correlations

Answer 2

can establish predictions, do not imply causation

Question 3

What is the Bradford-Hill criteria for causality

Answer 3

strength
consistency
specificity
temporality
biological gradient
plausibility
coherence
experiment
analogy

Question 4

What is strength relate to causality

Answer 4

larger association is more likely causal effect

Question 5

What is consistency related to causality

Answer 5

stronger association when same findings observed by different people and different samples

Question 6

How does specificity relate to causality

Answer 6

specific population with specific disease and no other likely explanation

Question 7

Larger specificy means what with causation

Answer 7

bigger probability of causal effect

Question 8

How does temporality relate to causation

Answer 8

effect happens after a cause

Question 9

How is biological gradient related to causation

Answer 9

more exposure= greater risk

Question 10

How is the degree of correlaiton measured

Answer 10

Pearson product-moment correlation coefficient

Question 11

What does the pearson product moment correlation coefficient measure

Answer 11

linear relationship between two variables

strength and direction of association

Question 12

What are the values of Pearson Product coefficient

Answer 12

+1 to -1

Question 13

What does a Pearson Product of 0 mean

Answer 13

no correlation

Question 14

What is R2

Answer 14

coefficient of determination; determines how well data fits a statistical model

Question 15

What is the alternative test for pearson test if data is skewed

Answer 15

Speraman’s rank

Question 16

What caution must be taken when using R2 values

Answer 16

do not know if the correlation is positive or negative, must have a graph to report that

Question 17

How is the degree of correlation measured in the Spearman’s rank test

Answer 17

p (rho)

Question 18

What does rho measure

Answer 18

extent to which as one variable increases, the other variable tends to increase

Question 19

What cannot a confidence level include

Answer 19

0

Question 20

What will be indicated if the confidence level includes 0

Answer 20

not considered significant

Question 21

What is the use of survival analysis

Answer 21

used to analyze data in which time until event is of interest

Question 22

What is selection bias

Answer 22

sample is not representative of the population

Question 23

What is Berkson bias

Answer 23

disease prevalance is estimated from hospital records

Question 24

What is measurement bias

Answer 24

leading questions

Question 25

What is Hawthorne effect

Answer 25

participant behavior altered by knowing they are being studied

Question 26

What is experimenter bias (pygmalion effect)

Answer 26

expected results are accidently communicated to participants

Question 27

What is lead-time bias

Answer 27

false estimate of survival rates; patients appear to survive longer after new screening test

Question 28

What is recall bias

Answer 28

Participants do not accurately recall events

Issue in retrospective studies

Question 29

What is late-look bias

Answer 29

participants with severe disease less likely to be identified because they die first

Question 30

What is confounding bias

Answer 30

a factor in a study is related to co-factor being examined

Question 31

WHat is design

Answer 31

choosing inappropriate study design to answer questions