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.

Which of the following is/are true about the Plan step of the veterinarian's significance test?

The alternative hypothesis is Ha:>12

The variable of interest is the number of races completed by race horses at the local track

A z-test will be needed because the standard deviation is known to be 6.8

The parameter of interest is the fact that race horses are supposed to average more than 12 races in their lives.

The null hypothesis is Ho:=15.3

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