Question

• A researcher claims that the average wind speed in a certain city is 8 miles per hour. A sample of 32 days has an average wind speed of 8.2 miles per hour. The standard deviation of the population is .6 miles per hour. At 5% level of significance is there enough evidence to reject the claim?

Answer 1

Not reject null hypothesis since the p value is greater than 0.05

Explanation:

We have the following:

z = (x ^ -m) / (sd / n ^ (1/2))

Let m be the mean that is 8, sd the standard deviation that is 0.6, n the sample size that is 32 and x the value to evaluate that is 8.2, replacing:

z = (8.2-8) / (0.6 / 32 ^ (1/2)) = 1.89

P (x> 8.2) = P (z> 1.89)

P (x> 8.2) = 1 - P (z <1.89)

We look for this value in the attached table of z and we have to:

P (x> 215) = 1 - 0.9713 (attached table)

P (x> 215) = 0.0287

since this is a two tailed test, the area of 0.0287 must be doubled the p value

the p value = 0.05794

Therefore, the decision is to not reject null hypothesis since the p value is greater than 0.05