Name: Banner ID: Exam1 6) A pollution study recorded the pollution indices from

Question

Name: Banner ID: Exam1 6) A pollution study recorded the pollution indices from S the stem-and-leaf plot. (Note: XIX means a pollution index of XX) selected sites and the result is shown in 1144 3125 410 What is the coefficient of variance for the data? a) 0.45 b)2.21 c) 27 d) 1221 7) You want to make a graph that shows the sales amounts for a grocery store in the past 10 years Agood choice of a graph would be a) Pie chart b) Stem-and-leaf plot c) Time series plot d) Box plot (8-9) A research study is to look at the relationship between students' class performance to their sports activities. A group of 100 students were selected. Their class performance are classified as Good or "Poor and sports activity classified as "Active" and "Not Active.* The number of students in each category is listed below Good Poor Total Active 54 15 69 Not Active 19 12 31 Total 73 27 100 Suppose we randomly select one student from the 100 8) What is the probability that the student is either good at classes or active in sports? a) 0.88 b) 0.73 c) 0.69 d) 0.54 9) Given that this student is active in sports, what is the probabdlity that the student is poor a classes? a) 69/100 b) 69/73 c) 15/69 d) 15/54 10) Let Z be a standard normal variable. Find the probablity P1 Zs3) a) 04772 b) 0.4987 c) 0.1574 d) 0.1359

Explanation / Answer

Mean = (14 + 14 + 32 + 35 + 40)/5
Mean = 135/5
Mean = 27

= ( (1/5-1) * (14-27)2+(14-27)2+(32-27)2+(35-27)2+(40-27)2)
= ( (1/4) * (-132 + -132 + 52 + 82 + 132))
= ( (1/4) * (169 + 169 + 25 + 64 + 169))
= 148.99864225
= 12.2065

Coefficient of Variance = /µ
= 12.2065 / 27
Coefficient of Variance = 0.45

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