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You are a researcher who conducted a study of soft-drink preferences among residents in a test market prior to an advertising campaign for a new cola product. Of the participants, 130 are teenagers an
A state meat inspector in Iowa has been given the assignment of estimating the mean net weight of packages of ground chuck labeled “3 pounds.” Of course, he realizes that the weights canno
A sample of 25 concession stand purchases at the May 12 matinee of Spider-Man 3 showed a mean purchase of $ 7.29 with a standard deviation of $ 3.02. For the May 18 evening showing of the same movie.
To test the hypothesis that students who finish an exam first get better grades, Professor Hardtack kept track of the order in which papers were handed in.
In Dallas some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made 143, 348 runs and had 20 accidents, while the flee
Interpret the following SPSS computer output for the chi-square test. Variable COMMUTE is “How did you get to work last week?” Variable GENDER is “Are you male or female?
Collapse the response categories in the following table so that it meets the assumption of the chi-square test; then perform the test.
Perform a chi-square test on the following data (a) Regulation is the best way to ensure a safe workplace.
An Excel Spreadsheet is reprinted below. Interpret the t-test results. Are they statistically significant?
The managers in a company’s East and West regions were rated on the basis of the company’s evaluation system. A researcher wishes to conduct a t-test of means to determine if there is a di
Test the hypothesis of no differences for average payback period (years) necessary to justify solar heating systems for residences.
A personnel manager has a computer-generated list of all employees that indicates that 70 percent are full-time employees, 20 percent are part-time employees, and 10 percent are furloughed or laid-off
One-half of a sample receives an incentive in a mail survey. The other half does not. A comparison of response rates is desired.
A random sample of 46 observations was selected from a normally distributed population. The sample mean was xbar=81, and the sample variance was s2=35.0. Does the sample show sufficient reason to conc
Select a variable that will enable you to compare proportions of two groups. Use sample sizes of at least 30. Use the z test for proportions to analyze the data.
If you wanted to determine which of the two learning programs made the bigger difference in the participant's knowledge and skills, what statistical tests would you perform? What assumptions would the
Suppose that the quarterly sales levels among health care information systems companies are approximately normally distributed with a mean of million dollars and a standard deviation of million dollar
200 students took a test. The scores were normally distributed. Your score was in the 60th percentile. How many people scored at or below your score?
The same survey was mailed to 500 adults aged 25–34 without the gift certificate. There were 65 responses from the first group and 45 from the second group. (a) Perform a two-tailed test compari
Two manufacturing facilities produce 1280 × 1024 LED (light-emitting diode) displays. Twelve displays are chosen at random from each lab, and the number of bad pixels is noted for each display.
From her firm’s computer telephone log, an executive found that the mean length of 64 telephone calls during July was 4.48 minutes with a standard deviation of 5.87 minutes.
Below are fertility rates (average children born per woman) in 15 EU nations for 2 years. (a) Make a scatter plot. (b) Find the correlation coefficient and interpret it.
A recent survey of 50 executives who were laid off from their previous position revealed it took a mean of 26 weeks for them to find another position.
As a condition of employment, Fashion Industries applicants must pass a drug test. Of the last 220 applicants 14 failed the test. Develop a 99 percent confidence interval for the proportion of applica