stat212 exam 1

response variable

outcome

explanatory variable

predict or explain

standard deviation

S & σ

S

statistics

σ

parameters

correlation coefficient

r & p

r

statistics

p

parameter

barplots

side by side box plots or jitter plots comparing means/medians

absolute error

distance between the specific estimate and the parameter

standard error

expected error when using it to estimate its parameter

standard deviation of a set of values when those values happen to be possible sample statistics

nominal

outcomes fall into categories with no ordinary scale

yes or no

what fruits do you like to eat

ordinal

outcomes that have a meaningful order but not a numeric scale

disagree neutral agree

discrete

numerical but limited values

how many days did you go to the gym

contiuous

numeric and measurable

how much do you weigh

bar plots

single categorical value

histogram

single numeric value

π

parameter representign a population proportion

p̂

statistic representing a sample population

μ

parameter for the population mean

x̄

statistic representing the sample mean

statistic

variable at the sample level

parameter

summary at the population level

when to use z test

when σ is known or well approximated

large number >= 100

when to use t test

σ is unknown and is estimated by s