# Statistics - Normal distribution

everyone! I have several questions that I have concerns about. Please, any help is appreciated.

A.Which of the variables below do you think will be roughly normally distributed?

a. Weights of 10 year old boys b. Incomes of 40 year old adults c. The numbers that show up when you roll a balanced die d. The amount of coffee which a filling machine puts into "4 ounce jars"

1. a only
2. a, b, c, d
3. a, b, d
4. a and d

B.Which of the following statements concerning the standard normal curve is/are true (if any)?

a. The area under the standard normal curve to the left of -3 is zero. b. The area under the standard normal curve between any two z-scores is greater than zero. c. The area under the standard normal curve between two z-scores will be negative if both z-scores are negative. d. The area under the standard normal curve to the left of any z-score is less than 1.

1.a, b 2.a, c 3.b, d 4.a

C.To identify a particular normal distribution, it is necessary to specify all of the following EXCEPT for: 1.the fact it is a normal distribution 2.the mean 3.the standard deviation 4.the z-score

D.In our classroom work regarding the standard normal curve, what does the notation F(z) represent?

1.the area between -z and +z 2.the area to the left of z 3.the area to the right of z 4.possibly any of the above

E.True or False: The "standard normal curve" is always a normal curve with mean 0 and standard deviation 1. 1.True 2.False

F.Consider two normal distributions, one with mean -4 and standard deviation 3 and the other with mean 6 and standard deviation 3. True or False: These two normal distributions are centered in the same place. 1.True 2.False

-
On homework problems, you should give your answers or guesses or thoughts. –  GEdgar Jul 3 '11 at 1:48
My answers are: A. 2; B. 3; C. 1; D. 2; E. 1; F. 2. Please, help me, if necessary. Thanks. –  user9636 Jul 3 '11 at 1:55
add comment

## 1 Answer

A: a. yes. b. No, these are more likely to be log-normal. c. No d. yes

a and d.

B: a. false b. yes; provided the z-scores are unequal. c. false d. true

b and d.

C: You do not need 4.

D: The normal cumulative distribution functoin

E: true

F: false; the mean is the center of the normal distribution.

-
add comment