PSY 550 Midterm Exam Assignment Paper

PSY 550 Midterm Exam Assignment Paper

PSY 550 Midterm Exam Assignment Paper

PSY550

PSY 550 Midterm Exam Latest-GCU

Question 1

For each of the research topics listed below, indicate the type of nonexperimental approach that would be most useful and explain why.

1. Pushing ahead in line

2. Daydreaming

3. Locating the most popular painting in an art gallery

4. Studiousness in college students

5. Determining whether a particular patient has improved with psychotherapy.

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Question 2

List the main sections (and subsections) of a research report.

Question 3

Compare and contrast the following terms: (a) test-retest reliability with inter-rater reliability, (b) content validity with both predictive validity and construct validity, and (c) internal validity with external validity. ·

Question 4

Define and describe the six steps of the scientific method. Give an example of each step.

Question 5

When designing survey questions, how would you control for each of the following response styles:

(a) willingness to answer,

(b) position preference, and

(c) yea- or nay-saying?

Question 6

Use Stevens’ model of measurement scales to answer these questions:

1. What type of scale is used when the variable is social class? Explain.

2. What type of scale is used when the variable studied is a Top 40 list of popular songs? Explain.

3. What type of scale is used when the variable studied is intelligence scores (for example, on the Stanford-Binet-R)? Explain.

4. What type of scale is used when the variables studied are low and normal birth weights of newborns? Explain.

Question 7

Contrast experimental with quasi-experimental methods; generally speaking, which methods are most useful?

Question 8

When is it appropriate for a researcher to use deception in a study? When is it not appropriate? How can the negative effects of deception be minimized?

Question 9

Researcher Sandy Beach found a correlation coefficient of +2.3 between variables X and Y. She is thrilled because that correlation is “like, way high.” She also feels that this answer “proves that X is like, causing Y.” What are three problems with Sandy’s conclusions?

Question 10

Contrast probability and nonprobability sampling methods; generally speaking, which methods are most useful?

PSY550 Chapter 8, module 17, Exercises 2 and 4 Solved

2.To test the hypothesis in Exercise 1, the admissions counselors select a random sample of freshmen and compare their scores on the SAT to those of the population of upper classmen. They find that the freshmen do in fact have a higher mean SAT score. However, what they are unaware of is that the sample of freshmen was not representative of all freshmen at Brainy University. Infact, the sample over-represented those with high scores and underrepresented those with low scores. What type of error (Type I or Type II ) did the counselors make?

ANSWER: The counselors made a Type I error. They rejected the null hypothesis that there was no relationship between grade level and SAT score when in fact the sample was skewed and they could not conclude that.

4.What are the appropriate H0 and Ha for each of the following research studies? In addition, note whether the hypothesis test is one-or two tailed.

a.A study in which researchers want to test whether there is a difference in spatial ability between left-and right-handed people.

ANSWER: Ho: There is no significant difference in spatial ability between left and righthanded people. Ha: There is a significant difference in spatial ability between left and righthanded people. The test comes under two-tailed test

1. A study in which researchers want to test whether nurses who work 8-hour shifts deliver higher-quality work than those who work 12-hour shifts.

ANSWER: Ho: There is no significant difference in quality of work done by the nurses in 8 hr shifts and 12 hr shifts. Ha: The nurses work in 8 hr shift done quality work then when they work in 12 hr shifts. Test comes under Right one-tailed.

1. A study in which researchers want to determine whether crate-training puppies is superior to training without a crate. ANSWER: Ho: There is no significant difference between crate training puppies and training puppies without a crate. Ha: The crate training puppies superior than training without a crate. The test comes under left one-tailed test.

Chapter 8, module 18, exercises 2 and 4

2.What is the standard error of the difference between means?

ANSWER: The difference between the means of two samples, A and B, both randomly drawn from the same normally distributed source population, belongs to a normally distributed sampling distribution whose overall mean is equal to zero and whose standard deviation (“standard error”) is equal to square. root[(sd2/na) + (sd2/nb)] where:

  sd2 = the variance of the source population (i.e., the square of the standard deviation);

  na = the size of sample A; and nb = the size of sample B.

To calculate the standard error of any particular sampling distribution of sample-mean differences, enter the mean and standard deviation (sd) of the source population, along with the values of na and nb, and then click the “Calculate” button.

4. A college student is interested in whether there is a difference between male and female students in the amount of time spent studying each week. The student gathers information from a random sample of male and female students on campus. Amount of time spent studying is normally distributed. The data follow.

Males              Females

27                    25

25                    29

19                    18

10                    23

16                    20

22                    15

• 19

1. What statistical test should be used to analyze these data? ANSWER: Two-sample T-test
2. Identify H0 and Ha for this study. ANSWER: Null: H0: There is no difference in study hours between male and female. Alternative: Hₐ: There is difference in study hours between male and female.
3. Conduct the appropriate analysis. ANSWER: Now since the data is normally distributed we can use the 2-sample t-test to test the Hypothesis. Here we can take our level of significance as 0.05 or a confidence level of 95%.
4. Should H0 be rejected? What should the researcher conclude? ANSWER: Ho is not rejected, and this means there is insufficient evidence here to reject the null hypothesis that the hours studied are different.
5. If significant, compute the effect size and interpret. ANSWER: T-Test of difference = 0 (vs not =): T-Value = -0.78 P-Value = 0.450 DF = 11

Individual Value Plot of Males, Females

Interpretation: Since the P-value(0.450) is greater than the significance level of (0.05) thus we can accept the null hypothesis and say that there is no difference in study hours for male and female.

1. If significant, draw a graph representing the data. ANSWER: Difference is not significant, thus no graph needed, because of interpretation:

Since the P-value(0.450) is greater than the significance level of (0.05) thus we can accept the null hypothesis and say that there is no difference in study hours for male and female.

References

Jackson, S. (2014). Research Methods: A Modular Approach (3rd ed). Belmont, CA: Wadsworth/Cengage Learning.