Answer:
a. The null and alternative hypothesis can be written as:
b. A Type I error is made when a true null hypothesis is rejected. In this case, it would happen if it is concluded that the actual mean outstanding credit card debt of college undergraduate is significantly less than $3173, when in fact it does not.
A Type II error is made when a false null hypothesis is failed to be rejected. In this case, the actual mean outstanding credit card debt of college undergraduate is in fact less than $3173, but the test concludes there is no enough evidence to claim that.
Step-by-step explanation:
We have a prior study of the mean outstanding credit card debt of college undergraduate that states that it was $3173 in 2010.
A researcher believes that this amount has decreased since then.
Then, he has to perform a hypothesis test where the null hypothesis states that the mean is still $3173 and an alternative hypothesis that states that the actual credit card debt is significantly smaller than $3173.
The null and alternative hypothesis can be written as: