Pediatricians claim that 3rd graders follow a normal distribution with a mean of 50 inches. You believe that the average height is less. So you want to test this out.

Ha (Alternative Hypothesis): Average height of 3rd graders < 50

H0 (Null Hypothesis): Average height of 3rd graders = 50

To do so, you take a sample of 30, 3rd graders. This sample has a mean of 47 inches, and a standard deviation of 2.1 inches?

Q20. You will calculate a left-tailed p-value for which of the following alternative hypotheses?

A. The average height of 3rd-graders is not equal to 50 inches (i.e., 3rd graders are either taller or shorter than 50 inches).

B. The average height of 3rd-graders is more than 50 inches (i.e., 3rd graders are taller than 50 inches)

C. The average height of 3rd-graders is less than 50 inches (i.e., 3rd graders are shorter than 50 inches)

Q21.

If your hypotheses are as follows:

Null Hypothesis: The average height of 3rd graders is equal to 50 inches.

Alternative Hypothesis: The average height of 3rd graders is less than 50 inches.

you will be calculating a _______ p-value.

A. Left-tailed p -value

B. Right tailed p-value

C. Two tailed p-value

Q22.

If your hypotheses are as follows:

Null Hypothesis: The average height of 3rd graders is equal to 50 inches.

Alternative Hypothesis: The average height of 3rd graders is more than 50 inches.

you will be calculating a _______ p-value.

A. Left-tailed p -value

C. Right tailed p-value

C. Two tailed p-value

Q23.

If your hypotheses are as follows:

Null Hypothesis: The average height of 3rd graders is equal to 50 inches.

Alternative Hypothesis: The average height of 3rd graders is not equal to 50 inches.

you will be calculating a __________ p-value.

A. Left-tailed p -value

B. Right tailed p-value

C. Two tailed p-value

Q24. How would you calculate the two-tailed p-value, if you know the one-tailed p-value?

A. 2 tailed p-value=One-tailed-p-value

B. 2 tailed p-value = 2 x one-tailed-p-value (i.e., p-value for the smaller tail)

C. 2 tailed p-value = .5 (half) x one-tailed-p-value (i.e., p-value for the smaller tail)

Q25. Why is 2 tailed p-value = 2 x one-tailed-p-value?

Two tailed p-value is the area under the curve that is occupied by samples that are as far away as your sample is from the population mean, ON BOTH SIDES.

What would that be on the following distribution?

A. A + B

B. C + D

C. A + D

D. B + C