Sophia Unit 5 test Questions & Answers Graded A

Sophia Unit 5 test Questions & Answers Graded AMike tabulated the following values for heights in inches of seven of his friends: 65, 71, 74, 61, 66, 70, and 72. The sample standard deviation is 4.577. Select the 95% confidence interval for Mike's set of data. 59.95 to 76.91 59.95 to 72.67 64.19 to 76.91 RATIONALE In order to get the 95% CI , we first need to find the critical t-score. Using a t-table, we need to find (n-1) degrees of freedom, or (7-1) = 6 df and the corresponding CI. Using the 95% CI in the bottom row and 6 df on the far left column, we get a t-critical score of 2.447. We also need to calculate the mean: So we use the formula to find the confidence interval: The lower bound is: 68.43 - 4.23 = 64.20 The upper bound is: 68.43 +4.23 = 72.66 *note that when rounding you can get values that might be slightly different but the values should be very close to what is calculated here. CONCEPT Confidence Intervals Using the T-Distribution 2 A table represents the number of students who passed or failed an aptitude test at two different campuses. East Campus West Campus Passed 39 45 Failed 61 55 In order to determine if there is a significant difference between campuses and pass rate, the chi-square test for association and independence should be performed. What is the expected frequency of East Campus and passed? 39 students 48.3 students 50.5 students RATIONALE In order to get the expected counts we can note the formula is: CONCEPT Chi-Square Test for Homogeneity 3 Brad recorded the number of visitors at the local science museum during the week:Day Visitors Tuesday 18 Wednesday 24 Thursday 28 Friday 30 He expected to see 25 visitors each day. To answer whether the number of visitors follows a uniform distribution, a chi-square test for goodness of fit should be performed. (alpha = 0.10) What is the chi-squared test statistic? Answers are rounded to the nearest hundredth. 1.40 1.12 2.54 RATIONALE Using the chi-square formula we can note the test statistic is