PUBH5018

Question 1

if distribution is skewed, what measure of central tendency shd you use?

Answer 1

median (and IQR)

Question 2

if distribution is symmetrical, what measure of central tendency shd you use?

Answer 2

mean (and SD)

Question 3

the bigger your sample size, the narrower your…what?

Answer 3

margin of error (confidence interval) and the more precise your estimate

Question 4

the 2 ways of drawing inference from a sample are:

Answer 4

including confidence intervals and doing hypothesis tests

Question 5

a normal distribution (not skewed) is defined by the

Answer 5

mean (the centre of the distribution) and SD (how spread out it is)

Question 6

what is a z value?

Answer 6

standardised normal deviation in a normal distribution

Question 7

what is an n value?

Answer 7

sample size

Question 8

what is an x value?

Answer 8

variable

Question 9

a low p value means the strength of evidence for rejecting the null hypothesis is..

Answer 9

strong (there is a likely effect)

Question 10

a p value above 0.05 (5%) means that…

Answer 10

statistically not significant (if yr dichotomising)

Question 11

which measure of uncertainty demonstrates practical (not statistical) importance?

Answer 11

confidence intervals (not p values)

Question 12

if yr sample size is small, what would you expect of your CI?

Answer 12

very large (no precision)

Question 13

if the CI contains a value of 0, the effect is what?

Answer 13

not significant

Question 14

what is standard deviation?

Answer 14

a measure of how spread out the datapoints are - a ‘standard’ difference from the mean

Question 15

what is a confidence interval?

Answer 15

range of possible values (effects) around a mean (best possible estimate)

Question 16

what is a z score?

Answer 16

the number of standard deviations that a value (x) is from the mean - use it look up in Table F1

Question 17

what is an x bar value?

Answer 17

sample mean

Question 18

what’s the difference btwn categorical or continuous variables?

Answer 18

categorical - in groups (sex, diagnosis, a scale)

continuous - keep going (height, blood pressure)

Question 19

what’s the difference btwn sampling and non-sampling errors?

Answer 19

sampling error - sample not large enough

non-sampling error - sample not representative enough

Question 20

what’s the difference btwn simple random sampling and stratified random sampling?

Answer 20

simple - purely randomised

stratified - pop initially divided into groups and then randomised