Question

A random sample of 160 car crashes are selected and categorized by age. The results are listed below. The age distribution of drivers for the given categories is 18% for the under 26 group, 39% for the 26-45 group, 31% for the 45-65 group, and 12% for the group over 65. Calculate the chi-square test statistic

χ to test the claim that all ages have crash rates proportional to their driving rates.
1. Under 26 = 66 drivers
2. 26-45 = 39 drivers
3. 46-65 = 25 drivers
4. Over 65 = 30 drivers

Answer 1

25.05

Explanation:

Given that a random sample of 160 car crashes are selected and categorized by age. The results are listed below. The age distribution of drivers for the given categories is 18% for the under 26 group, 39% for the 26-45 group, 31% for the 45-65 group, and 12% for the group over 65.

<26 26-45 46-65` >65

Observed O 66 39 25 30 160

Expected E 40 40 40 40 160

Chi square

(O-E)^2/E 16.9 0.025 5.625 2.5 25.05

Thus we get chi square test statistic = 25.05