Answer Happy

1 At your part-time job in the office, your manager requested that you examine all accounts receivable of the company, and then to take a random sample of them to provide her with estimates of the population values useful for decision making. You considered a random sample of 45 of the accounts and obtained a mean of $135.40 and a standard deviation of $43.72. Assuming normality for the distribution of amounts in the accounts receivable, estimate the upper end point in a 99% confidence interval for the total amount of the 780 accounts of the company.
The partial results below are based on a sample of recently trained workers, to determine if the number of hours of training time received (X, in hours) has helped in improving the time taken to troubleshoot a process problem (Y, in minutes) Summary Statistics Variable X Y N Mean Variance Corrected SS (SSxx) 25 6.76 4.77 114.56 25 17.18 18.41 441.84 Parameter Estimates Parameter Standard Variable Estimate Error Intercept 29.97451 0.69096 Training (X) -1.90747 0.09744 Standard Error 1.04297 R-Square 0.9434 Given that a worker has received 405.6 minutes of training, what is the lower end point in a 90% prediction interval for the time taken to troubleshoot a process problem?
1 A local community association wants to poll a random sample of its 305 members to estimate the proportion likely to attend a late spring function. The number of sample observations should be sufficiently large to ensure that a 99% confidence interval for the population extends at most 0.05 on each side of the sample proportion. How large of a sample is necessary? a