A business school dean is contemplating proposing a change in the requirements for graduation. At present, business majors are required to take one science course, chosen from a list of possible courses. The proposal is that this be replaced by the r..
A business school dean wanted to assess the importance of factors that might help in predicting success in law school. For a random sample of 50 students, data were obtained when students graduated from law school, and the following model was fitted:..
A business school placement director wants to estimate the mean annual salaries 5 years after students graduate. A random sample of 25 such graduates found a sample mean of $42,740 and a sample standard deviation of $4,780. Find a 90% confidence inte..
A campus administrator has found that 60% of all students view courses as very useful, 20%, as somewhat useful, and 20%, as worthless. Of a random sample of 100 students taking business courses, 68 found the course in question very useful, 18, somewh..
A campus finance officer finds that, for all parking tickets issued, fines are paid for 78% of the tickets. The fine is $2. In the most recent week, 620 parking tickets have been issued.
a. Find the mean and standard deviation of the number of these ..
A campus student club distributed material about membership to new students attending an orientation meeting. Of those receiving this material 40% were men and 60% were women. Subsequently, it was found that 7% of the men and 9% of the women who rece..
A candidate for office intends to campaign in a state if her initial support level exceeds 30% of the voters. A random sample of 300 voters is taken, and it is decided to campaign if the sample proportion supporting the candidate exceeds 0.28.
A car salesperson estimates the following probabilities for the number of cars that she will sell in the next week:
a. Find the expected number of cars that will be sold in the week.
b. Find the standard deviation of the number of cars that will be s..
A car-rental company has determined that the probability a car will need service work in any given month is 0.2. The company has 900 cars.
a. What is the probability that more than 200 cars will require service work in a particular month?
b. What is ..
A car-rental company is interested in the amount of time its vehicles are out of operation for repair work. State all assumptions and find a 90% confidence interval for the mean number of days in a year that all vehicles in the company’s fleet are o..
A charitable organization solicits donations by telephone. Employees are paid $60 plus 20% of the money their calls generate each week. The amount of money generated in a week can be viewed as a random variable with a mean of $700 and a standard devi..
A charity has found that 42% of all donors from last year will donate again this year. A random sample of 300 donors from last year was taken.
a. What is the standard error of the sample proportion who will donate again this year?
b. What is the prob..
A charity solicits donations by telephone. It has been found that 60% of all calls result in a refusal to donate; 30% result in a request for more information through the mail, with a promise to at least consider donating; and 10% generate an immedia..
A Chicago radio station believes that 40% of its listeners are younger than 25 years of age. Six hundred listeners are chosen at random.
a. If the station’s belief is correct, what is the probability that more than 260 of these listeners are younger ..
A city is divided into 50 geographic subdivisions. An estimate was required of the proportion of households in the city interested in a new lawn-care service. A random sample of three subdivisions contained 611, 521, and 734 households, respectively...