Click on the following links. Please note these will open in a new window.
Identifying hypotheses and understanding the differences between one-way ANOVAs and independent samples t tests.
Your book discussed the conditions under which you would perform an independent samples t test and a one-way ANOVA. The hypotheses for these tests were also discussed. In this activity, you will apply this information.
Go to the following website: http://news.berkeley.edu/2017/04/11/shoe-string-theory-science-shows-why-shoelaces-come-untied/
Scroll down to the diagram of the knots. Pretend you are investigating this shoe-coming-undone phenomenon. Assume the dependent variable is number of times each knot comes untied, and each person in your (imaginary) study was randomly assigned to tie their shoe using one of the knots only.
- Generate a hypothesis using the available knots as groups. Use the term mean differences in your hypothesis.
- What type of test would you use to test the hypothesis?
- Now go to this website: https://www.fieggen.com/shoelace/secureknot.htm
- Using a similar type of assignment as the above (imaginary) study, pretend you are examining the two ways to tie the shoes identified in the above study in addition to Ian’s Secure Knot method.
- Generate a hypothesis for your three ways of tying the shoes, with the knowledge that Ian’s Secure Knot is supposed to be nearly fail-proof.
- What test would you use to test the hypothesis?
Understanding assumptions of one-way ANOVA
Your book discussed the three assumptions of one-way ANOVA. In this exercise, you will apply that knowledge.
- What are the three assumptions of one-way ANOVA?
- Go to this website http://www.jiposhy.com/2013/10/coca-cola-vs-pepsi-vs-rc-cola.html
- What are the independent and dependent variables?
- What are the levels or values of the independent variable?
- Look at the sampling method, then scroll down to the first rating section. What assumption of one-way ANOVA is violated here?
- Look at the first rating set.
- Using the identified values as an average for each group, identify five additional data points that, if they were true data points, would not violate the assumptions of normality or homogeneity of variance.
- Using the identified values as an average for each group, identify five additional data points that, if they were true data points, would violate the assumptions of normality or homogeneity of variance.
Deciding when to do post hoc analysis
Your book discussed when to do post hoc analyses. In this activity, you will apply this information.
Go to the following website: https://www.pinterest.com/pin/107101297358341310/?lp=true
Imagine that you are quality control for Pinterest and tasked with the job of determining if the person who made the chart has any basis for classifying the movie characters in this manner. That is, do the people in the different groups differ in height in a statistically significant way?
Open up SPSS and create a variable for group (values: small, medium, and large) and height. Enter the data from the chart and run the analysis. If necessary, conduct pos hoc analyses. Answer the following questions.
- You should have used a one-way ANOVA. Explain why that test is appropriate.
- What is the hypothesis? What are the post hoc hypotheses in this case?
- When you ran the analysis, what indicated your need to do or not do post hoc analysis?
- What did the analyses indicate regarding group classification? Which groups (if any) were different from each other?