FROM CHAPTER 6 and 7, NORMAL DISTRIBUTION AND SAMPLING

Instructor: Asiye Aydilek

PART 1- Multiple Choice Questions

____ 1. For the standard normal probability distribution, the area to the left of the mean is

a.

–0.5

c.

any value between 0 to 1

b.

0.5

d.

1

Answer: B

The total area under the curve is 1. The area on the left is the half of 1 which is 0.5.

____ 2. Which of the following is not a characteristic of the normal probability distribution?

a.

The mean and median are equal

b.

The mean of the distribution can be negative, zero, or positive

c.

The distribution is symmetrical

d.

The standard deviation must be 1 o Answer:D

Normal distribution is symmetric. So, mean=median

The mean could be any number.

The standard deviation is positive but it is not always 1.

____ 3. Larger values of the standard deviation result in a normal curve that is

a.

shifted to the right

c.

narrower and more peaked

b.

shifted to the left

d.

wider and flatter

Answer: D

The Total area under the curve is 1. If the standard deviation is larger, it means the curve is wider, but the height is lower.

____ 4. Which of the following is not a characteristic of the normal probability distribution?

a.

Symmetry

b.

The total area under the curve is always equal to 1.

c.

99.72% of the time the random variable assumes a value within plus or minus 1 standard deviation of its mean

d.

The mean is equal to the median.

Answer: C

By the empirical rule, 68% of the time the random variable assumes a value within plus or minus 1 standard deviation of its mean

____ 5. The mean of a standard normal probability distribution

a.

is always equal to zero

c.

can be any value

b.

can be any value as long as it is positive

d.

is always greater than zero

Answer: A

____ 6. The standard deviation of a standard normal distribution

a.

is always equal to zero

c.

can be any positive value

b.

is always equal to one

d.

can be any value

Answer:B