The supervisor of a fish hatchery measures the length of a particular species every week after hatching to track their growth. If their average length is too short or too long, they do not mature properly and further tests must be done to determine the cause. She randomly selects 30 fish from among those that hatched 5 weeks ago and measures their individual lengths in inches to determine if they have grown to an average length of 9.7 inches. The alternative hypothesis reflecting her concern is that the population mean length of these fish is 9.7 inches.

The alternative hypothesis reflecting her concern is that the population mean length of these fish is not equal to 9.7 inches

Step-by-step explanation:

From the question we are told that

  The sample size is  n =  30  

 Generally the null hypothesis is that the population mean length of these fish that hatched  5 weeks ago  is  9.7 inches

Generally the the alternative hypothesis is that the population mean length of these fish that hatched  5 weeks ago is not equal to  9.7 inches

The reason why the alternative hypothesis is the above statement is that from the question we are told that If their average length is too short or too long, they do not mature properly(what this statement implies is that the mean length must be 9.7 inches after 5 weeks if it is to mature properly )

the answer will be

-2

7 - 9 = -2

reversed:

-2 + 9 = 7