## Multiple choice questions

Take the quiz test your understanding of the key concepts covered in the chapter. Try testing yourself before you read the chapter to see where your strengths and weaknesses are, then test yourself again once you’ve read the chapter to see how well you’ve understood.

The degree to which a statistical model represents the data collected is known as the:

1. Fit
2. Homogeneity
3. Reliability
4. Validity

If we calculated an effect size and found it was r = .42 which expression would best describe the size of effect?

1. Small
2. Small to medium
3. Medium to large
4. Large

What is the relationship between the sum of squared errors (SS), the sample size (n) and the variance (s2)?

1. SS = s2/(n – 1).
2. s2 = SS(n – 1).
3. n = (s2/SS) – 1.
4. s2 = SS/(n – 1).

#### Answer: s2 = SS/(n – 1)

If we use the mean as a model, what does the variance represent?

1. The average error between the model and the observed data.
2. The total error between the model and the observed data.
3. The squared total error between the model and the observed data.
4. The square-rooted average error between the model and the observed data.

#### Answer: The average error between the model and the observed data

Given a test is normally distributed with a mean of 30 and a standard deviation of 6:

• What is the probability that a single score drawn at random will be greater than 34?
• What is the probability that a sample of 9 scores will have a mean greater than 34?
• What is the probability that the mean of a sample of 16 scores will be either less than 28 or greater than 32?