SECTION 10.2 Independence 545 21. College Visits The contingency table shows the results of a survey asking 1858 parents and students of different incomes whether they visited their college before enrolling. At a = 0.01, can you conclude that family income is related to college visits? (Adapted from Sallie Mae) College visit before enrolling Family income In person Virtual tour Both Neither Less than $35,000 155 60 88 53 $35,000 –$100,000 461 136 171 85 Greater than $100,000 415 52 130 52 22. Choosing a College The contingency table shows the results of a survey asking 1858 parents and students of different incomes what their deciding factor was in choosing a college. At a = 0.01, can you conclude that the deciding factor in choosing a college is related to the income of the family? (Adapted from Sallie Mae) Deciding factor in choosing a college Family income Finances Academics Personal factors Not sure Less than $35,000 138 121 78 14 $35,000 –$100,000 290 298 239 26 Greater than $100,000 168 298 175 13 23. Vehicles and Crashes You are studying the relationship between types of vehicles and their points of initial impact in crashes with occupant fatalities. As part of your study, you randomly select 3000 vehicle crashes with occupant fatalities and organize the resulting data as shown in the contingency table. At a = 0.05, can you conclude that the types of vehicles and the points of initial impact of crashes with occupant fatalities are dependent? (Adapted from Insurance Institute for Highway Safety) Point of initial impact Vehicle type Front Side Rear Cars 1435 697 161 Pickup trucks 523 150 34 24. Alcohol-Related Accidents The contingency table shows the results of a random sample of fatally injured passenger vehicle drivers (with blood alcohol concentrations greater than or equal to 0.08) by age and gender. At a = 0.05, can you conclude that age is related to gender in such alcohol-related accidents? (Adapted from Insurance Institute for Highway Safety) Age Gender 16 –20 21 –30 31 – 40 41 –50 51 – 60 61 and older Male 27 148 107 71 66 54 Female 9 45 26 17 16 14
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