stats

Question 1

parametric tests

Answer 1

normally distributed
> students test - paired / unpaired

pearsons product moment coefficient-correlation

Question 2

non parameteric test
compares ordinal, interval, or ratio scales of unpaired data

Answer 2

mann-whitney u test

Question 3

used to compare proportions or percentages e.g. compares the percentage of patients who improved following two different interventions

non parametric

Answer 3

chi-squared test

Question 4

number needed to treat

Answer 4

NNT = 1 / absolute risk reduction

Question 5

absolute risk reduction

Answer 5

control event rate -treatment even rate

a- control group outcome/total

b- treatment outcome / total

=

Question 6

sensitivity is

Answer 6

true positive / (true positive and false negatives)

45/(45+155)

45/200

Question 7

specificity

Answer 7

true negative

TN /( Tn +FP)

Question 8

negative predicitive value

Answer 8

TN/ TN+FN

Question 9

type 2 error?

Answer 9

failure to reject null hypothesis