After an Idea or a Clinical Situation First Emerges as a Potential
A survey was recently conducted to determine if consumers spend more on computer-related purchases via the Internet or store visits. Assume a sample of 8 respondents provided the following data on their computer-related purchases during a 30-day period. Using a .05 level of significance, can we conclude that consumers spend more on computer-related purchases by way of the Internet than by visiting stores?
The following independent samples show the delivery times for two suppliers of raw materials (in days). A company currently uses Supplier A but will switch to Supplier B if its average delivery time is less than that for Supplier A. Use Excel to conduct the appropriate hypothesis test. Use .10.
Starting annual salaries for business school graduates majoring in finance and management information systems (MIS) were collected in two independent random samples. Based on previous studies, the population standard deviations for Finance and MIS salaries are estimated to be $2,100 and $2,600, respectively. Use the following data to develop a 95% confidence interval estimate of the difference between the starting salaries for the two majors.
A manager is thinking of providing, on a regular basis, in-house training for employees preparing for an inventory management certification exam. In the past, some employees received the in-house training before taking the exam, while others did not. Independent random samples taken from the company's records provided the following exam scores for 10 workers who did not receive in-house training and 8 workers who did receive training. (The manager is confident that the distributions of both populations' exam scores are approximately normal.)
a. Develop a 95% confidence interval estimate for the difference between the average test scores for the two populations of employees.
b. Using a = .05, test for any difference between the average test scores for the two populations of employees.