5.2 Grouped Data

When data sets get particularly large, it is usually better to consider grouping the data rather than consider each data point individually.

Some things to consider:

• You generally want in between 5 and 20 groups

• Groups must be of equal size

• You don't want any data points on a group boundary

Ex 1 p. 94# example 2

On a spreadsheet:

(a) Enter the data for the temperature in column A.

(b) Calculate the range of the data.

(c) Would it be better to use 5 3 degree groups or 8 2 degree groups?

(d) Put a heading for the group in column B and the midpoint of the group in column C and then group the data accordingly.

(e) Construct a relative frequency polygon and a cumulative frequency polygon.

(f) On how many days was the maximum temperature 25 degrees or less? On how many days did the temperature exceed 30 degrees?

Do example 3 similarly

Categorical Data

Sometimes discrete data is not measured numerically, but rather by some non-numerical category. For example: hair colour, blood type, favorite food would all be categorical data. Bar graphs can be used to analyze categorical data as can pie charts or pictograms.

Do p. 98 example 4 on a spreadsheet and create a pie chart for it.

*Same homework as last day*