Statistics Chapter 4

In a population with µ = 20, what is the deviation score for x = 28?

+8

In a population with µ = 20, what is the deviation score for x =12?

-8

A population of N = 80 scores, has µ = 20 and σ = 4. What is the population variance (σ2)?

16

A sample consists of n = 16 scores. How many of the scores are used to calculate the range

2

A population of N = 50 scores, has µ = 14 and σ2 = 9. What is the population standard deviation?

3

A sample of n = 5 scores has ΣX = 30 and ΣX2 = 376. What is the value of S2 for this population (computational formula)?

49

In general, what is the relationship between standard deviation and variance?

Standard deviation is the square root of variance

Calculate variance and standard deviation for the following sample of 3, 6, 1, 6, 5, 3

s = 2; s2 = 4

Calculate variance and standard deviation for the following sample of scores: 2, 4, 4, 8, 12

s = 4; s2 = 16

On an exam with a mean of μ = 70, you have a score of X = 75. Which of the following values for the standard deviation would give you the highest position within the class?

σ =1

Identify the values that represent about 95% of the of scores in a symmetrical, normal distribution with a µ = 30 and σ = 5:

20 and 40

Identify the values that represent about 68% of the of scores in a symmetrical, normal distribution with a µ = 30 and σ = 5:

25 and 35

For the following sample 10, 8, 5, 5, 7 of scores, calculate variance and standard deviation. Use two decimal places. Sample variance (s2) equals ____ and sample standard deviation equals _____

4.50, 2.12

The sum of the squared deviation scores is SS = 20 for a sample of n = 5 scores. What is the variance for this sample?

5

A sample of n = 5 scores has ΣX = 30 and ΣX2 = 376. What is the value of S for this population (computational formula)?

7

For the following sample 9, 6, 2, 6, 2 of scores, calculate variance and standard deviation. Sample variance (s2) equals ____ and sample standard deviation equals ____

9,3