A human resources consulting firm wants to estimate the average salary of university graduates with a bachelor's degree in science, and 10 years of working experience, in the Toronto area. A sample of 50 such employees reveals an average of $56,387 and a standard deviation of $5,435. Assuming the salary data are approximately normally distributed, construct a 90% confidence interval for the salaries.
Answer to relevant QuestionsA company wants to estimate the proportion of smokers on staff to within 5%, with 99% confidence. A preliminary estimate of the proportion of smokers is 0.1867. How big a sample size is necessary? Return to the confidence interval you constructed for Develop Your Skills 8.2, Exercise 6. The owner of the supermarket claims that the average household grocery bill is $95. Does the sample evidence support the owner's ...A random sample of 25 families leaving a supermarket yields an average grocery bill of $112.36, with a standard deviation of $32.45. A histogram of the data is approximately normal. Construct a 95% confidence interval for ...A college wants to estimate the proportion of its students who live at home with their parents. How large a sample size should be taken if the desire is to estimate the proportion to within 3%, with 98% confidence? Past ...A college surveys incoming students every year. An excerpt of one such survey, for business students only, is available in MyStatLab (you may have looked at this data set for the Test Your Knowledge exercise at the end of ...
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