Reference no: EM132180803

Assignment

Chapters 12 and 13, Description, Correlation, and Inferential Statistics

1. In an experiment, one group of research participants is given 10 pages of material to proofread for errors. Another group proofreads the same material on a computer screen. The dependent variable is the number of errors detected in a 5-minute period. A .05 significance (alpha) level is used to evaluate the results.

a. What statistical test would you use? Why?

b. What is the null hypothesis? The research hypothesis?

c. Describe a Type I error for this example.Describe a Type II error for this example.

d. What is the probability of making a Type I error?

2. In Professor Dre's study, the average number of errors detected in the print and computer conditions was 38 and 13, respectively; this difference was not statistically significant. When Professor Seuss conducted the same experiment, the means of the two groups were 21 and 14, but the difference was statistically significant. Explain how this could happen.

3. Suppose that you work for the child social services agency in your county. Your job is to investigate instances of possible child neglect or abuse. After collecting your evidence, which may come from a variety of sources, you must decide whether to leave the child in the home or place the child in protective custody. Specify the null and research hypotheses in this situation. What constitutes a Type I and a Type II error? Is a Type I or Type II error the more serious error in this situation? Why?

4. Dr. Topo is interested in knowing if yearly income (in dollars) is related to gun ownership (yes/no). Use the tables on page 288 that provide the correct statistical test to help identify the answer to part C.

a. What is the dependent variable? What scale of measurement is the DV measured?

b. What is the independent variable(s)? What scale of measurement is the IV measured?

c. What statistical test should be used to test this hypothesis?

5. Dr. Chico is interested in knowing if happiness (measured on a scale from 0-100) is associated with hours per day spent on the internet and body mass index (BMI). Use the tables on page 288 that provide the correct statistical test to help identify the answer to part C.

a. What is the dependent variable? What scale of measurement is the DV measured?

b. What are the independent variable(s)? What scale of measurement is the IV measured?

c. What statistical test should be used to test this hypothesis?