Page 122 - Data Science class 10
P. 122
Example 1.4: A survey of eighty people (40 men and 40 women) was taken on what genre of movie they would
choose to watch, and the following responses were recorded:
• 12 men preferred comedy/family sas-bahu movies.
• 12 men preferred action movies.
• 16 men preferred horror movies.
• 22 women preferred comedy/family sas-bahu movies.
• 11 women preferred action movies.
• 7 women preferred horror movies.
The information collected is used to build the following two-way table:
Category Comedy Action Horror Total
Men 12 12 16 40
Woman 22 11 7 40
Total 34 23 23 80
1.4.1. Interpreting Two-way Frequency Tables
The entries in the table are counts. The table has numerous features:
• Categories are in the left column and top row.
• The counts are located in the centre of the table.
• The totals are at the end of each row and column.
• A sum of all counts (a total) is placed at the bottom right.
For example, in the table given below, the rows of the table tell us whether it's a male or a female and the columns
of the table tell us if they own a car or not. Each cell tells us the number (or frequency) of people. For example, 20
females own a car.
Category Owns a car Don’t own a car Total
Men 55 5 60
Woman 20 40 60
Total 75 45 120
Activity 1
Record how many of your near and dear ones like cricket and how many of them like football. Create a
two-way relative frequency table with the data.
1.4.2. Two-way Relative Frequency Table
The two-way frequency type of table and the two-way relative frequency type of table are extremely similar. The
main difference is that, here we take percentages rather than numbers. Tables of two-way relative frequency show
the percentage of data points that fall into each group. Depending on the context of the issue, you can use either
row relative frequencies or column relative frequencies.
Let us see the below two-way table recording preferences of male and female architecture students with regard to
their choice of the subject as Landscaping or Interior Decoration.
120 Touchpad Data Science-X

