The test scores of 20 students on a 100-point test were recorded. 72 91 92 | 85 73 75 84 84 77 58 83 88 65 61 73 79 67 64 74 86 (a) Create a stem and leaf plot for the data. (Enter numbers from smallest to largest separated by spaces. Enter NONE for stems with no values.) stem leaf 5 6 7 8 Can you reasonably assume that these test scores have been selected from a normal population? O Yes, the stem and leaf plot indicates that this is a reasonable assumption. O No, the stem and leaf plot indicates that this is not a reasonable assumption. (b) Calculate the mean and standard deviation of the scores. (Round your standard deviation to three decimal places.) mean standard deviation (c) If these students can be considered a random sample from the population of all students, find a 95% confidence interval for the average test score in the population. (Round your answers to three decimal places.) to

You want to examine the relationship between dropping out of high school and delinquency. You have a random sample of 11 students. You have the number of delinquent offenses that each student reported committing in the year before and after dropping out of school. The following table shows the data. Student Before dropping out After dropping out 1 5 7 2 9 5 3 2 3 4 7 7 5 8 11 6 11 13 7 8 4 8 8 10 9 5 7 10 2 1 11 9 3 From performing a hypothesis test to determine if the mean number of delinquent differs after dropping out, what is the obtained t?

7) 16 63

NO ck)2 (2k)b