1.The state highway department is studying traffic patterns on one of the busiest highways in the state. As part of the study, the department needs to estimate the average number of vehicles that pass an intersection each day. A random sample of 64 days gives us a sample mean of 14,205 cars and a sample standard deviation of 1,010 cars. What is the 98 percent confidence interval estimate of , the mean number of cars passing the intersection?

QUESTION 8

1.A mail-order business prides itself in its ability to fill orders in less than six calendar days, on average. Periodically, the operations manager selects a random sample of customer orders and determines the number of days required to fill the orders. On one occasion when a sample of 39 orders was selected, the average number of days was 6.65 with a population standard deviation of 1.5 days. What is the critical value for = .10 to test the hypothesis that the time to fill is less than 6 days?

QUESTION 10

1.Standard X-ray machines should give radiation dosages below 5.00 milliroentgens. To test a certain X-ray machine, a sample of 36 observations is taken, with a mean of 4.13 mR and a population standard deviation of 1.91 mR. Calculate the appropriate test statistic to test the hypothesis.

QUESTION 15

1.In testingH₀:p .33; versusH_A:p< .33, with= .20 andn= 100, what is the value of the test statistic?

QUESTION 24

1.When sample size is 11, find t_.10