1. A veterinarian knows that race horses are not supposed to average more than 12 races in their lives. He suspects that a local race course is not following the guideline of averaging at most 12 races per horse. From records at a local race course, he randomly selects 20 race horses. The mean and standard deviation of the number of races per horse are respectively 15.3 races and 6.8 races.

The correct procedure for the veterinarian's test is:

1-sample z because we are testing a population mean and we don't know the population mean

1-sample t because we are testing a population mean and we don't know the population standard deviation.

1-sample t because we are testing a population mean and we don't know the population mean

1-sample t because we are testing a population mean and we have a small sample.

1-sample z because we are testing a population mean and we have a large sample

1-sample z because we are testing a population mean and we do know the population standard deviation.

2. A veterinarian knows that race horses are not supposed to average more than 12 races in their lives. He suspects that a local race course is not following the guideline of averaging at most 12 races per horse. From records at a local race course, he randomly selects 20 race horses. The mean and standard deviation of the number of races per horse are respectively 15.3 races and 6.8 races.

The state step for the veterinarian is:

How strong is the evidence that the average number of races per horse for all horses at the local race track is different from 12?

How strong is the evidence that the average number of races per horse for all horses at the local race track is less than 12?

We are testing whether the average number of races per horse for all horses at the local race track is less than 12

How strong is the evidence that the average number of races per horse for all horses at the local race track is equal to 12?

We are testing whether the average number of races per horse for all horses at the local race track is 12

How strong is the evidence that the average number of races per horse for all horses at the local race track exceeds 12?