## For the scores in the following table, what is the value of ΣX2 = ?

### statistics

##### Description

Section A

Multiple choice questions (1 mark each)

Section total: 10 marks

Answer ALL of the following questions by selecting the most correct answer and writing down the corresponding letter.

1.              For the scores in the following table, what is the value of ΣX2 = ?

X       F

4       1

3       2

2       1

1       3

a. 30

b. 41

c. 65

d. 225

2.              After 5 points are subtracted from every score, the sample mean is found to be M = 24. What was the mean for the original sample?

a. 29

b. 24

c. 19

d. Cannot determine without knowing the number of scores in the sample

3.              A vertical line drawn through a normal distribution at z = –1.00 separates the distribution into two sections, the body and the tail. What proportion of the distribution is in the body?

a. 0.8413

b. 0.1587

c. 0.3413

d. –0.1587

4.              Which of the following is a requirement for a random sample?

a. Every individual has an equal chance of being selected.

b. The probabilities cannot change during a series of selections.

c. There must be sampling with replacement.

d. All of the other 3 choices are correct.

5.              A population of N = 5 scores has ΣX = 20 and ΣX2 = 100. For this population, what is the value of SS?

a. 20

b. 80

c. 100

d. 380

6.              A population has SS = 100 and σ² = 4. What is the value of S(X – m) for the population?

a. 0

b. 25

c. 100

d. 400

7.              A population distribution has σ = 6. What position in this distribution is identified by a z-score of z = +2.00?

a. 2 points above the mean

b. 2 points below the mean

c. 12 points above the mean

d. 12 points below the mean

8.              What is the standard error of M?

a. The sample mean

b. The sample standard deviation

c. The mean of the distribution of sample means

d. The standard deviation of the distribution of sample means

9.              What happens to the expected value of M as the sample size increases?

a. It increases

b. It decreases

c. It stays constant

d. The expected value does not change in a predictable manner when the sample size increases