1.The file P07_02.xlsx contains data on the 1995 students who have gone through the MBA program at State University. You can consider this the population of State
University’s MBA students.
Round your answers to two decimal places, if necessary and if your answer is negative value, enter “minus” sign.
a. Find the mean and standard deviation for each of the numerical variables in this population.
Mean
Standard Deviation
Age
Children
GMAT Score
Previous Salary
Monthly Expenses
School Debt
Find the following proportions:
The proportion of students who are male.
The proportion of students who are international (not from the USA).
The proportion of students under 30 years of age.
The proportion of students with an engineering undergrad major.
2.b. Using the method in this section (not StatTools), generate a simple random sample of 100 students from this population, and find the mean and standard deviation
of each numerical variable in the sample.
Mean
Standard Deviation
Age
Children
GMAT Score
Previous Salary
Monthly Expenses
School Debt
3. The file P07_14.xlsx contains a very small population of only five members. For each member, the height of the person is listed. The purpose of this problem is to
let you see exactly what a sampling distribution is. Find the exact sampling distribution of the sample mean with sample size 2. (If necessary, round your answers to
four decimal places.)
Mean of sampling distribution
Standard deviation of sampling distribution
Verify that Equation (7.1) holds, that is, the mean of this sampling distribution is equal to the population mean.
4. . A manufacturing company’s quality control personnel have recorded the proportion of defective items for each of 500 monthly shipments of one of the computer
components that the company produces. The data are in the file P07_07.xlsx. The quality control department manager does not have sufficient time to review all of these
data. Rather, she would like to examine the proportions of defective items for a sample of these shipments. For this problem, you can assume that the population is the
data from the 500 shipments.
a. Use Excel to generate a simple random sample of size 25 from the data.
b. Calculate a point estimate of the population mean from the sample selected in part a. What is the sampling error, that is, by how much does the sample mean
differ from the population mean?
c. Calculate a good approximation for the standard error of the mean.
d. Repeat parts b and c after generating a simple random sample of size 50 from the population. Is this estimate bound to be more accurate than the one in part b?
Is its standard error bound to be smaller than the one in part c?
