In a study of car accidents and drivers who use cell phones,the following sample data are collected: Determine the expected frequencies those who had accidents in the last year to use for the chi-square test of independence.
A)23.0,46.0
B)27.8,41.2
C)189.5,189.5
D)34.5,34.5

Question

In a study of car accidents and drivers who use cell phones,the following sample data are collected:  Determine the expected frequencies those who had accidents in the last year to use for the chi-square test of independence.
A)23.0,46.0 
B)27.8,41.2 
C)189.5,189.5 
D)34.5,34.5

Quizplus · Accepted Answer

The expected frequencies can be calculated by taking the totals of each row and column and using them to find the expected frequencies based on the assumption of independence. The total number of people who had accidents in the last year is 69, and the total number of people who use cell phones while driving is 79. The total sample size is 200. Using these totals, we can calculate the expected frequencies for each cell as follows:

Expected frequency for those who had accidents and use cell phones: (69/200) x 79 = 27.8
Expected frequency for those who had accidents and do not use cell phones: (69/200) x 121 = 41.2
Expected frequency for those who did not have accidents and use cell phones: (131/200) x 79 = 51.2
Expected frequency for those who did not have accidents and do not use cell phones: (131/200) x 121 = 78.8

Therefore, the best choice is B, with expected frequencies of 27.8 and 41.2.

In a Study of Car Accidents and Drivers Who Use