Ch 11 Mock Exam Solutions

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East Los Angeles College *

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Chemistry

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Jun 1, 2024

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Ch 11 Mock Exam Solutions 1. OnJanuary 1, 2004, it becomes mandatory for all police departments in Illinois to record data pertaining to race from every traffic stop. Mundelein, lllinois, has been collecting data since 2000. Rather than using census data to determine the racial distribution of the village, they thought it better to use data based on who is using the roads in Mundelein. So they collected data on at-fault drivers involved in car accidents in the village and obtained the following distribution of race for users of roads in Mundelein. Race White African American Hispanic Asian P | Proportion 0.719 0.028 0.207 0.046 The following data represent the races of all 9868 drivers who were stopped for a moving violation in the village of Mundelein in a recent year. Race White African American Hispanic Asian L1 O | Number 7079 273 2025 491 Test that the distribution of race in traffic stops reflect the distribution of drivers in Mundelein Use 0.05 level of significance. L2 E Expected [ 7095.092 276.304 2042 676 453.928 ] df- k-1=3 Claim: pO=p1=p2=p3=p4 null: pO=p1=p2=p3=p4 E = n*p since frequencies are not equal alt: at least one is different X*2GOFTest There is not sufficient evidence to warrant rejection of the claim that alphaj 0.05 the distribution of race in traffic stops reflect the distribution of drivers p-value: 0.354 in Mundelein. p-value>alpha fail to reject the null

2. A2007 New York Times poll found that 315% of Americans attend religious services every week, 12% almost every week, 145% once or twice a month, 24%a few times a year, and 19% never. A survey taken this year of 100 randomly selected Americans showed 32 who attend religious services every week, 10 almost every week, 15 once or twice a month, 25 a few times a year, and 18 never. Test the claim that the population proportions have changed since 2007, use a 0.10 level of significance. Claim: at least one proportion is different null: po: 5 alt atleast one s different Everyweek almosteveryweek once or twice amonth few imesayear never n:100 P[0.31 0.12 014 024 0.19] alpha:0.10 a4 Ol32 10 15 2 18] E[31 12 14 24 19] pvalue: 0.970 . < sumcent evence & ere s not sufficient evidence to alpha:0.10 P-value>alpha support the claim that the population proportions altorefect the ngi_ Nave changed since 2007. 3. A statistics teacher clims that, on the average, 20% of her students get a grade of A, 35% get B, 25% get a C, 10% get a D, and 10% get an F. The grades of a random sample of 100 students were recorded. The following table presents the results. Grade 2 5 < 5 3 O [Observed 28 41 20 6 5 Use the 0.05 level of significance to test the claim that the grades follow the distribution claimed by the teacher. (020 035 025 01 01 n:100 E[20 35 25 10 10) alpha:0.05 drd Claim: p0=p1=p2= null: pO=p1=p: alt: at least one is different There is not sufficient evidence to warrant rejection of the claim that the alpha:0.05 grades follow the distribution claimed by the teacher. p-value: 0.0534 P-value>alpha fail o reject the null

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