I want to ask question 3 Section 114 Problems 13 For these p

Section 11.4 Problems 1-3. For these problems, you must complete a hypothesis test with all S steps listed in the module summary for this unit, including your calculation of the test statisticr I. Auto price and satisfaction. The table below shows the customer satisfaction rating and the cost (in 0.10, can thousands of dollars) for a random sample of 9 different models of automobiles. At a you conclude that there is a correlation between customer satisfaction and the auto cost 2742 1.69 2. Weight and reading time. The table below shows the weight and the reading time (in minutes per day) for a random sample of 10 different men. At o 0.05, can you conclude that there is a coreb tion between the men\'s weight and the time spent reading lbs) (Min 183 182.3 90.9 103.7 19.9 116.0 1920 18.5 85.6 122.3 185 3. High school average and GPA at graduationhe table below shows the high school average (in points) and the grade point average (GPA)at graduation for a random sample of 1O different stadents Using rank correlation, at 0.05, can you conclude that there is a correlation between the high school average and the first semester GPA? school average 83 91 86 83 86 84 84

Solution

ANSWER:

Let high school average be x variable and gpa at graduation be y.

now the formula for correlation coefficient = (n * sum of xy) - ( sum of x * sum of y) / ((n * sum of x^2 - (sum of x)^ 2 ) - ( n * sum of y ^ 2 - ( sum of y ) ^ 2 ) ) ^ 1 / 2

n = 10

r = 10 * 2215.42 - ( 831 * 26.67 ) / ( ( 10 * 69113 - (831) ^ 2 ) - ( 10 * 72.8907 - (26.67) ^ 2 ) ^ 1 / 2 = -0.0859

so the correlation rank is -0.0859 and the alpha is 0.05 , therefore we can say that that there is a moderate negative correlation , which means there is no relation beteen the high school marks and the first semester gpa.

HIGH SCHOOL AVERAGE (X)	83	83	84	77	86	83	86	84	83	82
GPA AT GRADUATION (Y)	2.42	2.91	3.16	2.47	2.09	2.86	2.84	2.1	2.4	3.42