Question

Suppose you believe the average weight of a certain collection of rainbow trout is 400 grams. A sample of weights of 40 rainbow trout revealed that the sample mean is 402.7 grams and the sample standard deviation is 8.8 grams. What is the p value of getting such a sample? Would you reject the null hypothesis at 95% significance level?

Answer 1

Solution :

= 400

=402.7

=8.8

n = 40

This is the two tailed test .

The null and alternative hypothesis is ,

H₀ :   = 400

H_a :     400

Test statistic = z

= ( - ) / / n

= (402.7-400) /8.8 / 40

= 1.94

P(z > 1.94) = 1 - P(z < 1.94) = 1-0.9738=0.0262

P-value = 0.0262

95% significant level

= 0.05  

P-value <

Reject the null hypothesis