Part 1 (multiple choice)

1. A researcher tested the effectiveness between two treatments for chronic headache pain. In reality, there was no difference in the pain relief between the treatments, which participants were assigned to randomly. In interpreting the data, the researcher rejected the null hypothesis. The conclusion of the study suggests.

a. A Type 1 error occurred b. A Type 2 error occurred c. no statistical errors occurred d. the wrong statistical analysis was conducted

2. Cognitive psychologists studied the effect of different fonts on reading comprehension. Participants read passages of equal length and complexity in Comic Sands font and in Courier font. After reading each passage, they completed a distraction task, and then were given comprehension tests. Results from a correlated groups t-test led them to fail to reject the null hypothesis; in reality, comprehension differed based on the font (Courier was better). The conclusion of the study suggests

a. A Type 1 error has occurred b. A type 2 error has occurred c. no statistical errors occurred d. the wrong statistical analysis was conducted

3. A researcher collected self-esteem scores from a sample of college students to see if they differed from the general adult population. In reality, the sample had higher self-esteem than the general population. Results from a one sample t-test led the researcher to reject the null hypothesis. The conclusion of the study suggests

a. A Type 1 error has occurred b. A type 2 error has occurred c. no statistical errors occurred d. the wrong statistical analysis was conducted

4. A researcher compared consumer attitudes towards products based on the packaging. The identical face lotion was packaged in two ways, one generic, the other "exclusive" with more expensive materials. In reality, participants didn't like the product at all regardless of packaging. In interpreting the data, the researcher failed to reject the null hypothesis. The conclusion of the study suggests.

a. A Type 1 error has occurred b. A type 2 error has occurred c. no statistical errors occurred d. the wrong statistical analysis was conducted

5. What is the critical value of z? Specify if the value is either "+/- " or "+ or -". a. for a two-tailed test, alpha = .05? b. for a one-tailed test, alpha = .05?

6. Many years of data indicated that the average office employee made 14.9 errors daily (with a standard deviation of 3.4). An organizational psychologist noted several environment modifications (wrist wrests, supportive office chairs, etc.) that she believed would decrease errors while maintaining high production levels. A sample of 20 employees were given one week with the new office equipment, and on the designated test day these employees averaged 11.2 errors.

a. Describe the statistical test to be done

b. State the null and alternative hypothesis

c. What is the critical value of the test statistic? What is the decision rule for rejecting the null hypothesis?

Hint: Draw the picture on a piece of paper of the rejection region to help with the direction/sign.

CV:

Reject H 0 if z

d. Calculate the observed value of the test statistic. Show your work for calculating both the standard error and z.

7. A university director wondered if STEM majors really were more introverted than the general population. They learned that the mean of a common Introversion measure is 85, and gave it to 61 students majoring in math. The mean Introversion score for the students was 92 with a standard deviation of 14. Are the STEM majors more introverted than the general population?

a. Describe the statistical test to be done [1 point].

b. State the null and alternative hypotheses [3 points].

c. What is the critical value of the test statistic, including df? What is the decision rule for rejecting the null hypothesis?

CV:

Reject H 0 if t

d. Calculate the observed value of the test statistic by hand, showing your work for the standard error and the statistic

e. Write out an conclusion about the research project. Use the context of the study in your answer

(please attach clear pictures if you are hand doing this)