Week 7: Planning for Your Data
Overview: This week, you will explore a few more inferential statistical tests and plan for your final assignment in Week 9.
Directions: Complete all six parts of this worksheet.
PART 1: WORKING WITH NOMINAL DATA
Amanda comes to you with questions about nominal data.
Directions: Answer Amanda’s questions about nominal data below.
Scoring Criterion: Describe nominal data and statistical analysis of nominal data.
What is nominal data?
How do you know if your data are nominal?
Can you use a mean to usefully describe nominal data? ☐Yes
☐No
Which statistical test can be used with two nominal variables?
Chi-Square Test
Since showing is often more powerful than telling, you choose to show Amanda how to use nominal data.
Directions: Complete the steps below.
Scoring Criterion: Perform a chi-square test (on the variables raclive and depress).
Create an appropriate null hypothesis for a chi-square test on the raclive variable and depress variable.
What would be the research question?
If you haven’t already, download the Raclive and Depress CSV file (save it where you can find it).
• In JASP, select the three blue bars, select open, find where you saved Raclive and Depress CSV file.
• Select Contingency Tables.
• Place raclive in the rows box.
• Place depress in the column box.
Copy and paste the resulting table below.
• Directions: Answer the questions in the table below.
• Scoring Criterion: Interpret chi-square test results.
If the ⍺ = 0.01, do you reject the null hypothesis? ☐Yes
☐No
If the ⍺ = 0.05, do you reject the null hypothesis? ☐Yes
☐No
Write your results using academic language and APA style.
PART 2: LOOKING FOR RELATIONSHIPS BETWEEN TWO VARIABLES
Correlation
Amanda has questions (doesn’t she always have questions?) about correlations.
Directions: Answer Amanda’s questions in the table below.
Scoring Criterion: Explain how a correlation differs from other statistical tests.
What is a correlation?
What does a positive correlation tell us about the relationship between two variables?
What does a negative correlation tell us about the relationship between two variables?
How is the relationship found in a correlation different from finding a difference between means (like in a t-test)?
Since the mathematical formula for a correlation involves a mean, could you find a Pearson’s correlation using nominal data as your dependent variable? Why or why not?
As with the chi-square test, you choose to show Amanda how correlations work.
Directions: Perform a correlation test by following the directions below.
Scoring Criterion: Perform a Pearson correlation test on the news and happy variables.
Using the variable news (how often respondent reads the news) and happy (how respondents rate their general happiness), create a null hypothesis and a research hypothesis.
Create a null hypothesis.
Create a research hypothesis.
If you haven’t already, download the News and Happy CSV file (save it where you can find it).
• In JASP, select the three blue bars, select open, find where you saved News and Happy CSV file.
• Select Regression, and then correlation.
• Place news and happy in the variables box.
• Put a check by Flag significant correlations.
• Put a check by the Display pairwise box.
• Put a check by the sample size box.
• Make sure the is a check by the report significance box.
Copy and paste the resulting table below.
Directions: Answer the questions in the table below.
Scoring Criterion: Interpret the results of a correlation test on the news and happy variables.
Is there a relationship? If yes, is it positive or negative in direction?
If the ⍺ = 0.01, do you reject the null hypothesis? ☐Yes
☐No
If the ⍺ = 0.001, do you reject the null hypothesis? ☐Yes
☐No
Write your results in academic language using APA style.
Juanita asks if a correlation could be found between how many hours a person reads the news and if they find life exciting.
Directions: Follow the directions below to perform a correlation test.
Scoring Criterion: Perform a Spearman’s rho test on the news and life variables.
What would be the null hypothesis?
What would be the research hypothesis?
If you haven’t already, download the News and Life CSV file (save it where you can find it).
• In JASP, select the three blue bars, select open, find where you saved News and Life CSV file.
• Select Regression, and then correlation.
• Place news and life in the variables box.
• Remove the check by Pearson’s r.
• Put a check by Spearman’s rho.
• Put a check by Flag significant correlations.
• Put a check by the Display pairwise box.
• Put a check by the sample size box.
• Make sure the is a check by the report significance box.
Copy and paste the resulting table below.
Directions: Answer the questions in the table below.
Scoring Criterion: Interpret the results of a Spearman’s rho test on the news and life variables.
If the ⍺ = 0.01, do you reject the null hypothesis? ☐Yes
☐No
If the ⍺ = 0.001, do you reject the null hypothesis? ☐Yes
☐No
How would you explain your results to a person who doesn’t know statistics?
Juanita also wants to look at more relationships between variables. For these, you will use the Spearman’s rho for practice.
Directions: Perform a Spearman’s rho test for each of the combination of variables listed in the chart below. Completely fill in the chart.
• In JASP, select the three blue bars, select open, find the .csv file you need.
• Select Regression, and then correlation.
• Place both variables in the variables box.
• Remove the check by Pearson’s r.
• Put a check by Spearman’s rho.
• Put a check by Flag significant correlations.
• Put a check by the Display pairwise box.
• Put a check by the sample size box.
• Make sure the is a check by the report significance box.
Scoring Criterion: Communicate hypotheses and results of a Spearman’s rho test. Note: Do not include screenshots, just fill in the table.
Variables:
wwwhr and mntlhlth Variables: wwwhr and life Variables:
wwwhr and happy Variables:
news and mntlhlth
Create a null hypothesis.
Create a research hypothesis.
Based on results: If the ⍺ = 0.01, do you reject the null hypothesis? ☐Yes
☐No
☐Yes
☐No
☐Yes
☐No
☐Yes
☐No
Report your results in APA style.
Explain the results in everyday language.
PART 3: WORKING WITH MORE THAN TWO GROUPS
ANOVA
Amanda has questions about how to analyze data if you have more than two groups or more than two variables.
Directions: Answer Amanda’s questions below.
Scoring Criterion: Explain how an ANOVA is different from other statistical tests.
Will a t-test or correlation work on more than two variables? ☐Yes
☐No
Will a t-test or correlation work on more than two groups? ☐Yes
☐No
You decide to demonstrate by running a factorial ANOVA looking at how mental health days are influenced by race and sex.
Description: Perform a factorial ANOVA.
Scoring Criterion: Perform an ANOVA (with variables mntlhlth, race, and sex).
What would be the three null hypotheses?
1.
2.
3.
What would be the three research hypotheses?
1.
2.
3.
If you haven’t already, download the Wwwhr and Mntlhlth CSV file (save it where you can find it).
• In JASP, click the three blue bars, select open, and then select Wwwhr and Mntlhlth CSV file from your saved files.
• Select ANOVA, and the ANOVA.
• Place mntlhlth in dependent variable box.
• Place both sex and race in the fixed factors box.
• Place a check next to estimates of effect size.
Copy and paste the resulting table below.
Directions: Answer the questions in the table below.
Scoring Criterion: Interpret the results of an ANOVA test.
If the ⍺ = 0.01, do you reject the null hypotheses? Which ones? ☐Sex
☐Race
☐Interaction – Sex x Race
If the ⍺ = 0.05, do you reject the null hypotheses? Which ones? ☐Sex
☐Race
☐Interaction – Sex x Race
Write the results in academic language using APA style and including effect size, assuming that the alpha level used is .05.
PART 4: REVIEWING THE STATISTICAL TESTS
Duante explains to Amanda that the chi-square test is best used for research questions like “Is there a significant relationship between being depressed and living in the Rocky Mountains?” The key is that it looks for relationships between yes/no questions or between factors that are not numerical. Amanda is still not certain about the uses of a chi-square, so you put together a table for her.
Amanda thinks she understands how to compute a correlation, but she still isn’t sure if she understands when to use a correlation. Duante explains that correlations are best for research questions like “Is there a significant relationship between reading scores and math scores?” The key with correlations is that it’s about the relationship between two numerical variables. Amanda is still unsure, so you build a table to help her out.
Duante explains that ANOVAs are best for research questions such as “Is there a difference in anxiety among men and women who live in different regions of the United States?” The key is that there are three or more groups to compare. Amanda wants you to build her a table so she can better understand.
Directions: Fill out the table below.
Scoring Criterion: Explain when to use different statistical tests.
Types of data for the independent variable (also called grouping variable or fixed factor in JASP) Types of data for the dependent variable This test is used to determine what type of relationship?
Options: Nominal, ordinal, interval, ratio
(note: some boxes will have just 1 of these options, other boxes will have multiple for a correct response)
t-test
Mann-Whitney
Chi-Square
Pearson’s Correlation
Spearman’s rho
ANOVA
PART 5: WORKING TOWARD YOUR PROJECT
You gather Duante, Amanda, and Juanita together to plan your archival data project. Amanda starts by asking what variables you will be looking at.
Directions: Complete the two tables below.
Scoring Criterion: Identify the research question, statistical test, variables, and hypotheses for the archival data project.
Step 1: Remembering your variables.
Fill in the table below. See your Week 3 assignment and any notes you had from the instructor.
First Variable Second Variable
Variable Name
Nominal, ordinal, or interval/ratio?
Duante asks what your statistical test will be and why. He also wonders about your research question and hypotheses.
Step 2: Choose the statistical test, research question, and hypotheses for your archival data project.
Statistical test chosen (see table in Part 4 for options).
Explain how you chose that specific statistical test.
Research Question
Hypotheses
HO:
H1:
Your instructor will give you feedback—pay attention to their comments on whether you chose the correct statistical test. Adjust your approach and your hypothesis based on their feedback.
PART 6: LOOKING TO YOUR FUTURE
Now that you’ve made the big decisions on your archival data project, Duante wonders if you’d consider a career that involves statistics.
Directions: Answer each of the questions below.
Scoring Criterion: Plan career contingencies based on accurate self-assessment of abilities, achievement, motivation, and work habits.
Step 1: Statistics and data analysis are marketable job skills. Search the Internet for jobs you could apply for with a bachelor’s degree that require the use of statistics. Some good, key search terms: psychology research assistance or survey data analysis.
Step 2: Answer the following questions in the table below.
Question Answer
What is the job title?
What are the educational requirements?
How would you assess your fit for this job? Write a paragraph that discusses your interests, current skills, and potential future skills.
If you’d like a job like this, discuss what you might need do to prepare for it. If you wouldn’t like a job like this, discuss why it wouldn’t be a good fit for you.
Provide the URL for the job opening you found.