Week6 Assignment 1

Question 1 – the concepts

Professor Nord stated that the mean score on the final exam from all the years he has been teaching is a 79%. Colby was in his most recent class, and his class’s mean score on the final exam was 77%. Colby decided to run a hypothesis test to determine if the mean score of his class was different than the mean score of the population. α = .05.

What is the mean score of the population?

What is the mean score of the sample?

Is this test one-tailed or two-tailed? Why?

What are the null and alternative hypotheses in this case?

Let’s pretend that p was calculated, and p = 0.09, should Colby reject or fail to reject the null hypothesis? Why?

What should Colby’s statement of conclusion be? (This circles back to what is being tested).

The next two ask you do to a hypothesis test. Remember, hypothesis tests follow a series of steps. They are not just a computer printout. Make sure if you use a computer printout, you identify which parts of the printout apply to the problem. All of the parts of the printout will NOT apply.

Question 2 – hypothesis test with guidance

A sample of 15 account balances of a credit company showed a mean customer balance of $4,300, but the marketing manager claimed that the mean balance for the population was $4425. The marketing manager did NOT have the population standard deviation, but the sample standard deviation was found to be $400. Use the p-value approach to conduct a full hypothesis test(all steps) that can be used to determine whether the mean of all account balances is significantly different from $4425. Let α = .01.

To help you go through the steps of hypothesis testing, follow these prompts:

The null hypothesis is

The alternative hypothesis is

I will use a (choose 1: t sub alpha over two / z sub alpha over two) in my formula because

I have calculated the value of t (or z) to be

I have used t (or z) to get the value of p (most likely from a chart or computer printout). My p value is

Alpha, which is given in the problem, is

When I compared p to alpha, p is (choose 1: greater than/less than) alpha.

Because of this, I know I should (choose 1: reject / fail to reject) my null hypothesis.

Choose one: The mean balance is different than $4425 / The mean balance is NOT different than $4425.

Question 3 -on your own

A sample of 350 homes for sale in ABC City showed a mean asking price of $247,000, but the city claimed that the mean asking price for the population was $253,000. The population standard deviation of all homes for sale was $8,000. Use the p-value approach to conduct a full hypothesis test (all steps- follow the guidance in the last problem) that can be used to determine whether the mean asking price is significantly less than $253,000. Let α = .10.