Frequency Distribution

frequency distribution

ways of organizing the data set that you observed

• show number of frequency for each vale

• high to low

• can be a table or graph

probability is between

0 - 1

percentage should add up to

100%

number of frequency should add up to

n number

3 types of frequency distribution graphs

histogram, polygon, bar graph

Histogram is when

you use touching bars to show interval of continuous data

histogram best for showing

the distribution of continuous data

histogram is easy to spot

skewness, normality, or outliers (meaningful shape)

histogram can’t be use for

categorical data

you can also have grouped

frequency distribution graph

polygon is

a line graph connecting points (midpoints of intervals) that represent frequencies

polygon is easier than histogram to

compare 2 distributions on the same graph

polygon isn’t as good for

showing precise frequency

bar graph is a graph with

separate bars (they don’t touch) showing frequencies (or percentages). of categories

bar graphs are best for

categorical or discrete data and easy to read and compare groups

bar graphs aren’t good for

continuous data

bar graphs doesn’t show

distribution shape like histogram

there are 2 general types of shapes of distribution

skewed and symmetric

researcher describe a distribution’s shape in words rather than

drawing

symmetrical distribution

each side is a mirror image of the other

skewed distribution

data pile up on one side and taper off in a tail

positive skew

tail on the right (few extreme positive score), wouldn’t want this for an exam score

negative skew

tail on the left (few extreme negative score), would want this for exam score

easy to remember tip for: positive skew

start with a lot and then down

easy to remember tip for: negative skew

start with low and the up