MCAT psych/soc statistics

sd

measure of how much each individual number differs from mean

68

normal distribution: ~____% of data are within +/- 1 SD of mean

95

normal distribution: ~____% of data are within +/- 2 SDs of mean

99.6

normal distribution: ____% of data are within +/- 3 SDs of mean

99.9, 0.1

normal distribution: ____th/____th percentiles correspond to +/- 3 SDs

98, 2

normal distribution: ____th/____nd percentiles correspond to +/- 2 SDs

84, 16

normal distribution: ____th/____th percentiles correspond to +/- 1 SD

power

likelihood that you have enough subjects to confirm hypothesis within acceptable margin of error

yes

do larger sample sizes always increase accuracy?

self-selection bias

occurs when people being studied chose whether to participate

t-test

used to calculate whether means of two groups are significantly different from each other

test-retest reliability

measure of degree to which assessment tool obtains similar scores over time

interrater reliability

measure of degree to which two raters have similar ratings of something they're assessing

external validity

refers to whether results can be generalized to other situations

construct validity

used to determine whether tool measures what it's supposed to measure