Biostatistics

Question 1

Statistical test: two qualitative variables

Answer 1

chi square test

Question 2

Statistical test: two quanitative variables

Answer 2

linear regression analysis

Question 3

Statistical test: Qualitative –> Quantitative > 30 population

Answer 3

Z test

Question 4

Statistical test: Qualitative –> Quantitative < 30 population

Answer 4

T-test

Question 5

Statistical test: Qualitative –> Quantitative > 3 groups

Answer 5

ANOVA

Question 6

Statistical test: Quantitative –> Qualitative

Answer 6

Regression analysis

Question 7

Statistical tet: reliability

Answer 7

Kappa statistic test

Question 8

Percentage: 1 standard deviation

Answer 8

68%

Question 9

Percentage: 2 standard deviations

Answer 9

95%

Question 10

Percentage: 3 standard deviations

Answer 10

99.5%

Question 11

Skewed to the left:

Mean is ___ than median

Answer 11

smaller

Question 12

Skewed to the right:

Mean is ___ than median

Answer 12

larger

Question 13

Scale: value of zero is arbitrary

Answer 13

Interval scale

Question 14

Scale: highest form, (+) clear zero point

Answer 14

Ratio scale

Question 15

Scale: lowest form, no intrinsic order

Answer 15

Nominal scale

Question 16

Scale: intrinsically ordered, but not quantitatively

Answer 16

Ordinal scale

Question 17

Proportion of true negative to those who tested negative

Answer 17

Negative predictive value

Question 18

Proportion of true positive to those who tested positive

Answer 18

Positive predictive value

Question 19

Proportion of true negative to those without disease

Answer 19

Specificity

Question 20

Proportion of true positive to those with disease

Answer 20

Sensitivity

Question 21

Screening test

Answer 21

Sensitivity

Question 22

Confirmatory test

Answer 22

Specificty

Question 23

TRUE OR FALSE

Sampling frame is necessary in simple random sampling

Answer 23

True

Question 24

TRUE OR FALSE

Sampling frame is necessary in stratified random sampling

Answer 24

False

Question 25

TRUE OR FALSE Sampling frame is necessary in cluster sampling

Answer 25

False

Question 26

Denominator in incidence rate

Answer 26

Person-years of observation

Question 27

Causes distortion of results because the factor is distributed unevenly in exposed and unexposed individuals The association between two variables is distorted by the fact that both are associated with a third Difference in crude and adjustment risks

Answer 27

Confounding

Question 28

Magnitude of the effect of a particular exposure on the outcome will vary according to the presence of a third factor

Answer 28

Effect modification

Question 29

Control for confounding: case-control studies

Answer 29

Matching

Question 30

Control for confounding: clinical trials

Answer 30

Randomization

Question 31

Control for confounding: large cohort studies

Answer 31

Analysis

Question 32

As prevalence decreases, the positive predictive value

Answer 32

Decreases

Question 33

As prevalence decreases, the negative predictive value

Answer 33

Increases

Question 34

Bias: when the screening test advances the time of diagnosis, but no true prolongation of life occurs because survival for persons who are screened and those who are not is the same from the time the cancer occurs

Answer 34

Lead bias

Question 35

Bias: screening test less likely will detect a rapidly progressive disease if symptoms rapidly develop because the window period between the time the cancer can be detected when it is asymptomatic by a screening test and the time it will become clinically significant is short

Answer 35

Length bias

Question 36

MIsclassification of exposure is not random Result in overestimate of an association

Answer 36

Differential misclassification

Question 37

When memory of exposure is unrelated to the fact that a person has a disease or not Consequence of an imprecise measurement of eitther exposure or outcome Causes the results to move towards the null (no association)

Answer 37

Nondifferential misclassification

Question 38

Ratio of the observed number to the expected number of deaths or cases of the disease

Answer 38

Standardized mortality or morbidity ratio

Question 39

Persons followed for variable lengths of time are counted according to the length of time they were followed

Answer 39

Survival anaylsis