A) A physiologist believes he has discovered a new steroid hormone that can control the blood glucose in mammals. In an experiment, he injects laboratory rats with a small amount of this steroid hormone and, after a suitable waiting period, measures the blood glucose level of the rats. The average level for a rat is 32.1, with a standard deviation of 3.9. In his fifteen experimental rats, he obtains an average blood glucose level of 34.4 with a standard deviation of 4.12. Assume that the criterion of a normal distribution is met for this example.

1- What is the appropriate statistical test to use? Briefly justify your answer.

2- What is the null hypothesis?

3- What is the alternative hypothesis?

4- Using an alpha of 0.05, what is the critical value?

5- What is the value of the obtained statistic?

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