# Multiple choice questions

Quizzes are available to test your understanding of the key concepts covered in each chapter. Click on the quiz below to get started.

1. What is the standard error?

- The standard error is the standard deviation of sample means.
- All of the options describe the standard error.
- The standard error is a measure of how representative a sample parameter is likely to be of the population parameter.
- The standard error is computed from known sample statistics, and it provides an unbiased estimate of the standard deviation of the statistic.

The correct answer is b) All of the options describe the standard error.

2. A scatterplot shows:

- Scores on one variable plotted against scores on a second variable.
- The frequency with which values appear in the data.
- The average value of groups of data.
- The proportion of data falling into different categories.

The correct answer is a) Scores on one variable plotted against scores on a second variable.

3. When interpreting a correlation coefficient, it is important to look at:

- The +/– sign of the correlation coefficient.
- The magnitude of the correlation coefficient.
- The significance of the correlation coefficient.
- All of these.

The correct answer is d) All of these.

4. The correlation between two variables *A* and *B* is .12 with a significance of *p* < .01. What can we

conclude?

- That there is a substantial relationship between
*A* and *B*.
- That variable
*A* causes variable *B*.
- That there is a small relationship between
*A* and *B*.
- All of these.

The correct answer is c) That there is a small relationship between *A* and *B*. This is because values of ±.1 represent a small effect, ±.3 is a medium effect and ±.5 is a large effect (although these canned effect sizes are no substitute for interpreting the effect size within the context of the research literature).

5. The relationship between two variables partialling out the effect that a third variable has on one of

those variables can be expressed using a:

- Partial correlation
- Semi-partial correlation
- Bivariate correlation
- Point-biserial correlation

The correct answer is b) Semi-partial correlation. This is because in a semi-partial correlation we partial out the effect that the third variable has on only one of the variables in the correlation.