**Question text**

An analysis of the final test scores in this class shows that the scores follow the normal distribution. The mean of the distribution is 75, and the standard deviation is 8. The professor wants to award an A to a student whose score is in the highest 10%, which means 90% of the class will have lower grades. What is the cut-off point (or score) for those students who earn an A versus those who earn a B? In other words, what is the lowest grade an A student can earn? Hint: Solve for x.

Select one:

a. 82.2

b. 64.7

c. 85.3

d. 96.9

**Q 3**

**Question text**

In a normal distribution of measurements having a mean of 500 feet and a standard deviation of 50 feet, what percent of the distribution falls between 490 and 520 feet?

Select one:

a. 63.26

b. 55.65

c. 23.47

d. 24.32

**Q 4**

**Question text**

You want to compare the cost of a one-bedroom and a two-bedroom apartment in the area. You collect data from 10 advertisements of each type of apartment. Here are the rents for the one-bedroom apartments (in dollars/month):

520, 645, 600, 505, 450, 550, 515, 495, 650, 385

Here are the rents for the two-bedroom apartments (in dollars/month):

605, 510, 580, 650, 675, 675, 750, 500, 495, 675

Do two-bedroom apartments rent for significantly more than one-bedroom apartments? What can you conclude? Assume alpha = 0.05.

**Select the appropriate conclusion:**

Select one:

a. p-value is approximately 0.019; two-bedroom apartments rent for significantly less than one-bedroom apartments.

b. p-value is approximately 0.974; two-bedroom apartments rent for significantly more than one-bedroom apartments.

c. p-value is approximately 0.026; two-bedroom apartments rent for significantly more than one-bedroom apartments.

d. p-value is approximately 2.084; two-bedroom apartments rent for the same as one-bedroom apartments.

**Q 5**

**Question text**

The following results were gathered from a survey where three toothpaste brands were tested by three groups. (For example, when 50 people tried Brand A toothpaste for a year, they got zero to one new cavities.)

Determine if there is a significant difference in the effectiveness of these toothpastes in preventing cavities.

**Select the appropriate conclusion.**

Select one:

a. At an alpha of 0.18 there is NOT a significant difference in the effectiveness of these three brands of toothpastes. Brand and cavities are independent.

b. At an alpha of 0.18 there is a significant difference in the effectiveness of these three brands of toothpastes. Brand and cavities are not independent.

c. At an alpha of 0.25 there is NOT a significant difference in the effectiveness of these three brands of toothpastes. Brand and cavities are independent.

d. At an alpha of 0.05 there is a significant difference in the effectiveness of these three brands of toothpastes. Brand and cavities are not independent.