Question

#1. To determine whether the pipe welds in a nuclear power plant meet specifications a random sample of welds is selected, and tests conducted on each. Weld strength is measured as the force required to break the weld. Suppose the specifications state that mean strength of welds should exceed 100lb/in?; the inspection team decides to test H:u= 100 versus H : > 100. Why is this better than H: 4 < 100 ?

Answer 1

Answer :

Given that :

Null hypothesis :

Ho :μ = 100

Alternative hypothesis :

H, :μ> 100

and the specifications state that mean strength of welds should exceeds 100

1b/in

i.e

μ> 100

and tha reverse should be

W<=100

If the equality should be less than or equal to(<=),then the null hypothesis is taken as

Ho :μ = 100

and Alternative hypothesis as

H, :μ> 100

Here '<' symbol is included in null hypothesis,so that we cannot use or consider for alternative hypothesis.