Question

To determine whether the pipe welds in a municipal power plant meet specifications, a random sample of welds is selected and tests are conducted on each weld in the sample. Weld strength is measured as the force required to break the weld. Suppose that the specifications state that the mean strength of welds should exceed 100 ponds per square inch. What is the appropriate null hypothesis?

Answer 1

`H_(0): \mu \leq 100\text{ ponds per square inch}`

Explanation:

We are given the following in the question:

Test:

To check weld strength of power plant

Specification:

The mean strength of welds should exceed 100 ponds per square inch

We can design the null and alternate hypothesis as:

`H_(0): \mu \leq 100\text{ ponds per square inch}\\H_A: \mu > 100\text{ ponds per square inch}`

Interpretation of null hypothesis:

The null hypothesis states that the mean weld strength is less than 100 ponds per square inch and does not meet the specifications.