standard deviation and whatnot

standard deviation

(often reported as ±) shows how much variation there is from the mean/avg

data points of smaller/larger standard deviations

• data points close together → smaller deviation

• data points spread out → larger deviation

what is standard error of the mean (SEM) used to represent

represents uncertainty in an estimation of mean & accounts for both sample size & variability

as standard error grow smaller…

smaller SEM → increased accuracy (accurate estimation of the population

what does the length of the error bars mean?

spread around the mean, shorter bars = less variability from the mean