A consumer products company wants to increase the absorption capacity of a sponge. Based on past data, the average sponge could absorb 3.5 ounces. After the redesign, the absorption amounts of a sample of sponges were (in ounces): 4.1, 3.7, 3.3, 3.5, 3.8, 3.9, 3.6, 3.8, 4.0, and 3.9. At the 0.01 level of significance, what is the decision rule to test if the new design increased the absorption of the sponge?
A)Reject null hypothesis if computed t is less than 2.580.
B)Reject null hypothesis if computed t is greater than 2.821.
C)Reject null hypothesis if computed z is 1.96 or larger.
D)Reject null hypothesis if computed t is less than 2.764.

Question

Quizplus · Accepted Answer

The decision rule for a one-tailed t-test at the 0.01 level of significance with 9 degrees of freedom (n-1 = 10-1) involves rejecting the null hypothesis if the computed t-value is greater than the critical t-value from t-distribution tables, which is approximately 2.821 for a 0.01 level of significance.

A Consumer Products Company Wants to Increase the Absorption Capacity