1. Week 11 Assignment: Chi-square

In a study of high school students at least 16 years of age, researchers obtained the survey results summarized in the table below (based on data from "Texting While Driving and Other Risk Motor Vehicle Behaviors Among U.S. High School Students" by O'Malley, Shults, and Eaton, Pediatrics,Vol. 131, No.6).

	Irregular Seat Belt Use?
	Yes	No
Texted While Driving	1737	2048
Did not Text While Driving	1945	2775

• State the null and alternative hypotheses.
• Assuming independence, what are the expected frequencies for each of these variables?
• What is the value of the X²statistic?
• Use a 0.05 significance level to test the claim of independence between texting while driving and irregular seat belt use. Are those two risky behaviors independent of each other? Calculate the chi-square manually or using Excel.