Author Question: Choo Choo Paper Company makes various types of paper products. One of their products is a 30 mils ... (Read 190 times)

Medesa · **on:** Jun 24, 2018

Choo Choo Paper Company makes various types of paper products. One of their products is a 30 mils thick paper. In order to ensure that the thickness of the paper meets the 30 mils specification, random cuts of paper are selected and the thickness of each cut is measured. A sample of 256 cuts had a mean thickness of 30.3 mils with a standard deviation of 4 mils.
a. Compute the standard error of the mean.
b. At the .05 level of significance using the critical value approach, test to see if the mean thickness is significantly more than 30 mils.
c. Show that the p-value approach results in the same conclusion as that of part b.

Question 2

An advantage of stratified simple random sampling is that
a. only a portion of the strata must be sampled.
b. estimates of population parameters for each stratum are automatically available.
c. desired precision and sample size are independent decisions.
d. the strata are automatically formed.

durant1234 · **Reply #1 on:** Jun 24, 2018

Answer to Question 1

a. .25
b. Test statistic t = 1.2 < 1.645; do not reject H0 . There is not enough evidence to conclude that the mean thickness is significantly more than 30 mils.
c. p-value (.1151) is between .1 and .2; do not reject H0.

Answer to Question 2

b