Question

There is concern that increased industrialization may be increasing the mineral content of river water. Ten years ago, the silicon content of the water in a certain river was 5 mg/L. Eighty-five water samples taken recently from the river have mean silicon content 5.4 mg/L and standard deviation 1.2 mg/L. a. Find the P-value. b. Do you believe it is plausible that the silicon content of the water is no greater than it was 10 years ago

Answer 1

a) P value = 0.0013

b) No, it is not plausible that the silicon content of the water is no greater than it was 10 years ago

Explanation:

The null hypothesis here is “Mean is equal to 5” while alternate hypothesis is that “Mean is greater than 5”

Given

Mean = 5, x’ = 5.4 and sigma = 1.2 and n = 85

Z = x-u’/sigma/sqrt n

Substituting the given values, we get –

Z = 3.02

A) P value = 0.0013 which is less than 0.05 and thus we will reject the null hypothesis

B) There is enough evidence to reject the null hypothesis