**Applied Statistics for Psychology**

**Unit 9 Assignment **

This is a course-level assessment assignment**. :** Interpret the output from an appropriate test of hypothesis for a particular context.

**HINTS AND HELP**

**Dataset: Psych_Data.xlsx can be found in the Virtual Office. You will use this data set to answer all of the questions in the Assignment. **

**Note: When asked to include the interpretation of the results and final conclusions, be sure to include all results, and interpretation of the meaning of the results, and final conclusions that a common person can understand.** **Make sure the conclusions are written in context based on the content in the question. Make sure you use complete sentences, paragraph form (single spacing), proper grammar, and correct spelling. Minimal or incomplete responses can lose points. Include any Excel results that you use, but do not include Excel results that are not part of your solution.**

**Hint: You are asked to determine “appropriate” tests and methods, and to make calculations. This means that you will have to determine which tests or methods are best and why. When asked for your p-value, if your Excel output shows something like 2.735E-15 (scientific notation for 2.735 x 10^(-15), go ahead and include this value from the output and realize this means the p-value is “near zero.” For your decision responses, you will want to compare your p-value to 0.05 and state whether you will reject Ho or fail to reject Ho. **

**Use the Live Binder for further assistance. There is a link to the Live Binder under every Unit.**

*****Assume alpha = .05 for all questions on this assignment*** **

1. Compare the different **Genders **of subjects in the Psych_Data.xlsx data set to determine if there is a *statistically significant difference* in the mean **Suicide Risk Levels (suicidal_inv) **between the different gender groups. Be sure to state the type of test, state the Ho and Ha, include all relevant Excel results and plots, and write final conclusions for the full results of the test in context. Be sure that your final conclusions are written in common terms for an average person to understand.

(a) What type of hypothesis test will you run?

(b) State the Ho and Ha.

(c) Include descriptive statistics (mean, standard deviation, sample size) __AND__ an appropriate graphical display that allows you to visually compare the **Suicide Risk Levels** for the two gender groups. Copy/paste the numerical summaries and graph here __AND__ describe the similarities and differences in the **Suicide Risk Levels** of the two groups (address central tendency and variation of the two groups in your discussion).

(d) Give the test statistic, p-value, and decision from your test results (Include Excel output).

(e) Write a full conclusion (in context) for the results on this test in a way that can be understood by a non-statistical person. This answer will be at least 100 words or more.

2. Compare the different **Socioeconomic Levels (ses_level)** of the students in the Psych_Data.xlsx dataset to determine if there is a *statistically significant difference *in the mean **Anxiety Scores (anx_score)** between the different SES levels. Be sure to state the type of test, state the Ho and Ha, include all relevant Excel results and plots, and write final conclusions for the full results of the test in context. Be sure that your final conclusions are written in common terms for an average person to understand.

(a) What type of hypothesis test will you run?

(b) State the Ho and Ha.

(c) Include descriptive statistics (mean, standard deviation, sample size) __AND__ an appropriate graphical display that allows you to visually compare the **Anxiety Scores** for the three SES groups. Copy/paste the numerical summaries and graph here __AND__ describe the similarities and differences in the **Anxiety Scores **of the three groups (address central tendency and variation of the three groups in your discussion).

(d) Give the test statistic, p-value, and decision from your test results (include Excel output). Would a post-hoc be necessary – why or why not?

(e) Write a full conclusion (in context) for the results on this test in a way that can be understood by a non-statistical person. This answer will be at least 100 words or more.

3. If you recall from Unit 7, you looked at how to measure the relationship (correlation) between any two quantitative variables. You also learned that if two variables are significantly correlated with each other, then one variable can be used to estimate or predict the other. The equation used to make this prediction is called a regression equation.

Use the following scatterplot and Excel output to answer the questions. The two variables in this case are **Depression Level (dep_scale) **and **Anxiety Score (anx_score)**.

(a) Based on the scatterplot, which variable is the independent variable? Which variable is the dependent variable?

(b) What is the value of the correlation coefficient? Using the scatterplot and the correlation coefficient, does the relationship appear linear? Is there a positive or negative association? Is the association weak, moderate, or strong?

(c) Based on the Excel output above, is there convincing evidence of a *significant linear relationship *between Anxiety Score and Depression Level (yes or no)? **Explain** how you know.

(d) Using the Excel output above, write your prediction equation (should be in the form ). Then, using your equation, predict the **Depression Level **for a subject with a **Anxiety Score** of 6.6 (round your answer to two decimal places). **SHOW WORK **for your calculation.

4. From the Psych_Data.xlsx dataset, use the** Before Therapy (pre_ther) **and** After Therapy (post_ther) **scores to answer the question: *“Does a short-term integrated therapy method lead to an **improvement **in one’s mental health status?” *Assume the **(pre_ther)** and **(post_ther) **scores are appropriate measures of one’s mental health state and the higher the score, the better one’s overall mental health.

(a) What type of hypothesis test will you run?

(b) State the Ho and Ha.

(c) Give the test statistic, p-value, and decision from your test results (include Excel output).

(d) Write a full conclusion (in context) for the results on this test in a way that can be understood by a non-statistical person. This answer will be at least 100 words or more.

5. From the Psych_Data.xlsx dataset, use the** gender **and** subs_abuse **variables to determine whether there is evidence of a* significant association *between gender and type of substance abuse (alcohol, narcotics, both, none).

(a) What type of hypothesis test will you run?

(b) State the Ho and Ha.

(c) Include an appropriate graphical display that allows you to visually assess the association between gender and type of substance abuse. Copy/paste the graph here. Comment on any association that appears to be present.

(c) Give the test statistic, p-value, and decision from your test results (include Excel output).

(d) Write a full conclusion (in context) for the results on this test in a way that can be understood by a non-statistical person. This answer will be at least 100 words or more.

**Submitting your Project **

**Make sure your name is on your project and saved to your computer (save the file as firstname lastname MM570 Assignment). When you are ready to submit your completed project, complete the steps below: **

• Click on Assignments at the top of your course page.

• Click on Unit 9 Assignment Dropbox.

• Click Add a File to attach your Word doc template (this should be the ONLY file you submit).

• Include any comments if you wish.

• Click SUBMIT.

• You should revisit the Dropbox to view any helpful feedback your instructor has left for you.

• Make sure that you save a copy of your submitted and returned assignment.