The National Safety Board wants to determine the effect of seat belt use on saving lives. One study showed data on children under the age of 5 who were involved in car accidents in which at least one fatality occurred. Below is the table: X1 Survivors (0) Fatalities (1) Total No belt (0) Adult belt (1) Child seat (2) 1129 509 1638 X2 432 73 505 733 139 872 Total 2294 721 3015 Answer in 2 decimal places. a) Determine the probability that a child will be in a child seat. b) Determine the probability that X1 = 0 given X2 = 0 c) What is the probability of X1 = 1 given X2 = 0?

Your statistics instructor often ponders the relationship between commute time and job satisfaction while driving back and forth to campus.  Your instructor hypothesizes that people with a shorter commute time will have higher degrees of job satisfaction.  Randomly sampling 600 Valley commuters, the instructor finds the following data listed in frequencies: Table 2: Commuters by Length of Commute and Job Satisfaction Job Satisfaction Number Who Commute 20 Minutes or Less Number Who Commute 21 to 40 Minutes Number Who Commute 41 Minutes or More Total Number for Each Level of Job Satisfaction Dissatisfied 10 60 140 210 Neutral 45 59 51 155 Satisfied 145 60 30 235 Total Number for Each Commute Time Range 200 179 221           1. Change frequencies to column percentages.

The following table shows some data from a study on substance use among 10th graders in the United States and Europe. Smoked Cigarettes Cigarette-Free Totals U.S. 14,000 Europe 96,000 Total 71,210 110,000

The National Hurricane Center provides data that list the number of large (category 3, 4, or 5) hurricanes that have struck the United States, by decade, from 1851-2020. Is there sufficient evidence that the number of large hurricanes have remained constant (per decade)? What are the degrees of freedom? Decade Count Decade Count 1851-1860 6 1941-1950 10 1861-1870 1 1951-1960 8 1871-1880 7 1961-1970 6 1881-1890 5 1971-1980 4 1891-1900 8 1981-1990 5 1901-1910 4 1991-2000 5 1911-1920 7 2001-2010 8 1921-1930 5 2011-2020 10 1931-1940 8     Chi-squared test for given probabilitiesdata:  stormsX-squared = 13.589, df = 16, p-value = 0.6293 A. 107                   B. 17                   C. 13.589                    D. 16