Reference no: EM132515158
In a random sample of 80 people, 52 consider themselves as baseball fans. Compute a 92% confidence interval for the true proportion of people consider themselves as baseball fans and fill in the blanks appropriately.
We are 92% confident that the true proportion of people consider themselves as baseball fans is between
From a sample of 550 items, 52 were found to be defective. The point estimate of the population proportion defective will be:
Senior management of a consulting services firm is concerned about a growing decline in the firm's weekly number of billable hours. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on work-related activities in a typical week. Rather than reviewing the records of all the firm's full-time employees, the management randomly selected a sample of size 50 from the available frame. The sample mean and sample standard deviations were 46.4 and 7.2 hours, respectively.
Construct a 97% confidence interval for the average of the number of hours this firm's employees spend on work-related activities in a typical week.
The percent defective for parts produced by a manufacturing process is targeted at 4%. The process is monitored daily by taking samples of sizes n = 160 units. Suppose that today's sample contains 14 defectives.
Determine a 88% confidence interval for the proportion defective for the process today.