stats exam 2

Scatterplot

shows relationship between 2 variables

central tendency 

value that represents similarities within the group 

variance 

value that represents differences within the group 

when is mean relavent

when data seem to follow a normal pattern

when is mode relavent

when there are only a small number of possible answers

when is median relavent

when there is a huge range of numbers with some being very far from others

choose mode when

there are only a few answer possibilities

variance

measure of variability

core of statistics

variety

measurements of variance

range and standard deviation

is range grounded by the scale of the variable

no

should mean be used for uneven distribution

no

standard deviation tells us the _____ of variability, not the_______ of variability

amount, pattern

if data is unevenly distributed, should mean be used for central tendency

no

when distribution is normal, are mean meadian and bode all equal

yes

central tendency + variability =

full picture

what graph is for one continuous variable only

histogram

are bars in a histogram all the same color

yes

x axis in a histogram is the

bin

y axis on a histogram is the 

frequency 

influential outlier

adds bias

if an outlier is >3 sd from the mean

discard it

histogram

only one continuous variable, y axis is count/frequency, individual level data

scatterplot

one continuous variable plus one categorical ORRRR continuous variable, individual data 

line graph

two continuous variables, group level data

bar graph

one continuous and one categorical variable, compares group level data

what is this

scatterplot

what are the variables in this scatterplot 

2 continuous 

what is this

scatterplot

what are the variables in this scatterplot 

one categorical and one continuous 

what is this

line graph

line graphs are only used for

continuous variables

line graphs measure if things are _____ and if theyre _____

changing different 

does the line in a line graph show central tendency

yes

does the line in a line graph show variance

no

visual represention of the standard deviation

error bars

what is this

bar gaph

what type of variable is on the x axis

categorical

what type of variable is on the y axis

continuous

what do descriptive statistics do

describe data

types of descriptive statistics

central tendency and variance

graph si pointy or flat, central tendency is ok

kurtosis

central tendencies are unequal, 

skewed