Question

Suppose that your financial aid allots a textbook stipend by claiming that the average textbook costs $88.87. You want to contest this claim. Based on a sample of 27 textbooks at the store, you find an average of $94.87 and a standard deviation of 11.4.

Answer 1

Answer)

Null hypothesis Ho : u = 88.87

Alternate Ha : u is not equal to 88.87

Sample mean = 94.87

Sample standard deviation = 11.4

As the population standard deviation is unknown, we will use t table, to conduct the test

Test statistics t = (sample mean- claimed mean)/(s.d/√n)

t = (94.87-88.87)/(11..4/√27)

t = 2.735

Degrees of freedom is given by sample size - 1

= 27-1

= 26

For df 26 and t = 2.735

P-value from t distribution is = 0.011084

As the p-value is small

We reject the null hypothesis

So, we have enough evidence to support the claim