Histograms

Question 1

Frequency Table

Answer 1

tabular representation of a data set to show how many observations fall in different categories.

Question 2

Histogram

Answer 2

A graphical representation of frequency table.

Question 3

Number of classes

Answer 3

Usually between 5 and 20
Aim is to use enough classes to show pattern in data but not so many that some contain few or no data.

Question 4

Class Limits

Answer 4

All data must fit within one class.
Minimum must account for smallest value expected.
Maximum must account for largest value expected.
We can have open ended classes if a few values are extreme compared to the majority.
Try to set category widths so that “breakpoints” are “nice rounds numbers

Question 5

Positively Skewed

Answer 5

Single peak with values extending further to the right than to the left.

Question 6

Negatively Skewed

Answer 6

Single peak with values extending further to the left than to the right

Question 7

Bimodal

Answer 7

Two distinct peaks.