Author Question: Describe the method of finding the area under the standard normal curve between z = 0 and z =- ... (Read 62 times)

audragclark · **on:** Jun 24, 2018

Describe the method of finding the area under the standard normal curve between z = 0 and z =- 1.33.

Question 2

Delivery time by courier services is important to stock brokers. One such firm wishes to estimate the average time taken by couriers delivering negotiable securities in New York City. Specifically, the firm randomly samples 36 courier pickup and delivery times. The collected data, in minutes, represent the time between pickup and delivery. Suppose the population standard deviation is 0.3 minutes and the sample mean is 9.975 . Find the sample mean and compute. A 90-percent confidence interval for the true mean delivery time, is:
a. 9.852 to 10.05.
b. 119.60 to 119.80.
c. 119.62 to 119.78.
d. 119.26 to 119.87.
e. 9.893 to 10.057.

djofnc · **Reply #1 on:** Jun 24, 2018

Answer to Question 1

Recall the property of symmetry. The area to the left of 0 to - 1.33 is the same as for the area to the right of 0 to 1.33 . Go down the left most column of the standard normal table to the row with 1.3 and right across the rows until in the column headed at the top with .03. The value is 0.4082, which is the area between z = 0 and z = -1.33.

Answer to Question 2

E