# Statistics - Null Hypothesis

A manufacturer 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. What is the decision rule at the 0.01 level of significance to test if the new design increased the absorption amount of the sponge?

a Do not reject null hypothesis if computed t is less than 2.580

b Do not reject null hypothesis if computed t is less 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

https://brainmass.com/statistics/hypothesis-testing/statistics-null-hypothesis-absorption-capacity-sponge-189349

#### Solution Preview

H0: x-bar - mu (not greater than 0) vs Ha: x-bar - mu > 0

n = 10, Degrees of freedom ...

#### Solution Summary

The expert examines the null hypothesis for absorption capacity of a sponge. Neat, step-by-step solution is provided.