Question

1.True or False: I want to test the hypothesis that the average SAT score of incoming freshmen is more than 1,100. If I am going to use an alpha value of .05, my statistics instructor tells me that this means plus or minus two (2) standard deviations

2.I wish to question the validity of a business assumption. If I perform a hypothesis test to test the validity, the acceptance of the null hypothesis indicates that the assumption is correct.

True

False

3. This semester’s average score on the first statistics exam for all statistics students was 73 with a population standard deviation of 5. In a random sample of 25 students from this semester's statistics classes, how likely would it be for the sample to have an average score of less than 72?

Answer 1

1. False

Using alpha value of .05 for one tail test, the critical value of test statistic, Z is 1.64. Thus we test if the test statistic is less than or greater than 1.645.

2.

False

The acceptance of the null hypothesis does not indicate that the assumption is correct. It indicates that there is not sufficient data to reject the null hypothesis.

3.

Mean of average score = 73

Standard deviation of average score = 5 / = 1

Probability that sample to have an average score of less than 72 = P[ < 72]

= P[Z < (72 - 73) / 1]

= P[Z < -1]

= 0.1587