Question

A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 4.3. A sample of 44 honors students is taken and is found to have a mean GPA equal to 4.4. The population standard deviation is assumed to equal 0.40. The parameter to be tested is O the mean GPA of 4.4 for the 44 selected honors students the mean GPA of all university students the proportion of honors students with a GPA exceeding 4.3 the mean GPA of all university honors students 0 Question 24 1 pts The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership. The dealership has historically had 800 customers per day. The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750. Assume that the population standard deviation is 310. The value of the test statistic is t99 = -1.6130 z = 1.6130 t99 = 1.6130 z = -1.6130

Answer 1

Ans the mean GPA of 4.4 for the 44 selected honors students

The hypothesis test is performed on the sample and accordingly the prediction is done for the entire population with a confidence level. In the scenario, the purpose is to establish mean GPA should exceed 4.3. The mean of 44 students is calculated as 4.4 with standard deviation of population as 0.4

24)

Z (<=X) = (X – Mean)/Standard deviation of sample

X = Observed value = 800

Mean = 750

Standard deviation of population = 310

Sample size = 100

Standard deviation of sample = Standard deviation of population/sqrt(Sample size) = 310/sqrt(100) = 31

Z = (800-750)/31 = 1.6130

Ans: z = 1.6130