Please answer all 1. In a normal distribution, the proportion of the scores within 1 standard deviation of the mean
Select one:
a. is determined solely by the population standard deviation
b. is approximately 95% regardless of the population mean and standard deviation
c. is determined solely by the population mean
d. is determined by both the population mean and standard deviation
e. is approximately 68% regardless of the population mean and standard deviation

2.Let y be a random variable that has the standard normal distribution. The value of P(y<1.5) is
Select one:
a. -0.0668
b. 0.4332
c. 0.0668
d. 0.9332

3.Scores on a Math test are normally distributed with a mean of 35.6 and a standard deviation of 8.7. Let X_bar be the sample mean of samples of randomly selected 32 students. Which of the following is true about X_bar?
Select one:
a. It is not normally distributed.
b. It is uniformly distributed.
c. It is normally distributed with mean 35.6 and standard deviation 8.7.
d. It is normally distributed with mean 35.6 and standard deviation 1.54.

4.The Central Limit Theorem describes the distribution of
Select one:
a. depending on the situation
b. sample means
c. population means
d. sample standard deviations
e. population standard deviations

5.Scores on a Math test are normally distributed with a mean of 35.6 and a standard deviation of 8.7. Let X_bar be the sample mean of samples of randomly selected 15 students. Which of the following is true about X_bar?
Select one:
a. It is not normally distributed since the sample size is small.
b. It is normally distributed since the population is normally distributed.
c. It is uniformly distributed.
d. It is normally distributed since the sample size is small.

6.Scores on a Math test are normally distributed with a mean of 35.6 and a standard deviation of 8.7. If 15 students are randomly selected, find the probability that the mean of their test scores is at least 35.
Select one:
a. 0.4361
b. 0.6053.
c. 29.73
d. 0.6932

7.Let y be a random variable that has the standard normal distribution. If P(0 Select one:
a. 0.3853
b. -0.3853
c. 0.6147
d. -0.6147

8.In a manufacturing plant that makes boxes, the width of a certain type of box is normally distributed. The probability that the width is less than 29.9825 cm is 0.0635 and the probability that the width is more than 30.0225 cm is 0.0246. What is the mean and the standard deviation of the box width respectively? (See Exercise 39 on page 243 in the textbook for an example).
Select one:
a. 24.0000 and 0.0200
b. 30.0000 and 0.0200
c. 24.0000 and 0.0115
d. 30.0000 and 0.0115

9.Let y be a random variable that has the standard normal distribution. The value of P(-1 Select one:
a. 0.4332
b. 0.9332
c. 0.2255
d. 0.7745

10.Scores on a Math test are normally distributed with a mean of 35.6 and a standard deviation of 8.7. Find a score that separates the top 75% from the bottom 25%.
Select one:
a. 5.87
b. 29.73
c. 41.47
d. 0.67