Ba 555 Practice Midterm
BA 555 Practical Business Analysis
Practice Midterm Examination
1. Re-do all problems in Practice Problem Set 1.
2. Dollar Car Rental Co. was originally named Dollar a Day Car Rental because they charged $1.00 per day to rent a car, plus a charge per mile driven. Many customers complained that the odometers on Dollar’s cars recorded more miles than were actually driven. To evaluate these complaints you take a random sample of 6 Dollar’s cars, drive them on a carefully measured 100-mile course, and record the miles driven as registered by the odometers. The results are 100, 105, 109, 102, 107, and 101, with the sample standard deviation around 3.578. a. Using these sample results, construct a 95% confidence interval for the population mean miles recorded by all Dollar cars for a 100-mile trip. b. As a legal consultant hired by the group of the customers who complained about the odometers, do you have enough evidence to support your clients’ claim? State your hypotheses (H0 vs. Ha), rejection region and both statistical and substantive conclusions.
3. The grades on the final examination given in a large organic chemistry class are normally distributed with a mean of 72 and a standard deviation of 8. The instructor of this class wants to assign an “A” grade to the top 10% of the scores, a “B” grade to the next 10% of the scores, a “C” grade to the next 10% of the scores, a “D” grade to the next 10% of the scores, and an “F” grade to all scores below the 60th percentile of this distribution. For each possible letter grade, find the lowest acceptable score within the established range.
4. The weekly demand for General Motors car sales follows a normal distribution with a mean of 40,000 cars and a standard deviation of 12,000 cars.
a. There is a 5% chance that GM will sell more than what number of cars during the next week? b. What is the probability that GM will sell between 20 and 23 thousand cars during the next week?
5. A
Practice Midterm Examination
1. Re-do all problems in Practice Problem Set 1.
2. Dollar Car Rental Co. was originally named Dollar a Day Car Rental because they charged $1.00 per day to rent a car, plus a charge per mile driven. Many customers complained that the odometers on Dollar’s cars recorded more miles than were actually driven. To evaluate these complaints you take a random sample of 6 Dollar’s cars, drive them on a carefully measured 100-mile course, and record the miles driven as registered by the odometers. The results are 100, 105, 109, 102, 107, and 101, with the sample standard deviation around 3.578. a. Using these sample results, construct a 95% confidence interval for the population mean miles recorded by all Dollar cars for a 100-mile trip. b. As a legal consultant hired by the group of the customers who complained about the odometers, do you have enough evidence to support your clients’ claim? State your hypotheses (H0 vs. Ha), rejection region and both statistical and substantive conclusions.
3. The grades on the final examination given in a large organic chemistry class are normally distributed with a mean of 72 and a standard deviation of 8. The instructor of this class wants to assign an “A” grade to the top 10% of the scores, a “B” grade to the next 10% of the scores, a “C” grade to the next 10% of the scores, a “D” grade to the next 10% of the scores, and an “F” grade to all scores below the 60th percentile of this distribution. For each possible letter grade, find the lowest acceptable score within the established range.
4. The weekly demand for General Motors car sales follows a normal distribution with a mean of 40,000 cars and a standard deviation of 12,000 cars.
a. There is a 5% chance that GM will sell more than what number of cars during the next week? b. What is the probability that GM will sell between 20 and 23 thousand cars during the next week?
5. A