# The Process of Statistical Analysis in Psychology

# Web Activities

Click on the following links. Please note these will open in a new window.

*Activity 1:*

Understanding the differences between independent samples *t* tests, one-way ANOVAs, and two-way ANOVAs

Your book discusses the conditions under which you would use several tests. Here you will practice differentiating between an independent samples *t* test, a one-way ANOVA, and a two-way ANOVA.

- Go to the following website: http://jackxmorris.com/posts/instagram-likes
- Scroll down to where it says “The importance of a caption.”

- Notice it refers to the median.

i.Why might it be best to use the median instead of the mean?

ii.What might this mean for the assumptions of the above three tests?

- For this assignment, ignore that it presents the median and pretend we are examining mean differences. This assignment is hypothetical and the dependent variable is continuous regardless of which measure of central tendency is presented.
- If you were examining the differences in mean likes for the with/without captions chart data, what test would you use? Why?

- Scroll down to where it starts to show data for likes based on time of day.

- Notice the data are presented as times of day (continuous).
- How might you turn the continuous variable into a grouping variable so you are conducting

- an independent samples
*t*test? - a one-way ANOVA?

- an independent samples

- Scroll down to the last line of the page. Given what you know about two-way ANOVA, what do you think about the conclusion? Specifically, does it include analysis of all independent variables presented on the page?
- Let’s say you had this information provided in the above two charts (time of day [morning/afternoon/evening] and caption [with/without]). How could you analyze this information?

- Would you analyze the information using the same test if you had the following variables and levels?

- time of day: between 0000–1200/1201–1159
- caption: with/without

- Would you analyze the information using the same test if you had the following variables and levels?

*Activity 2:*

**Identifying hypotheses of two-way ANOVA**

Your book discusses the hypotheses of two-way ANOVA. In this activity, you will apply this information.

- Go to the following website: http://flowingdata.com/2015/11/30/most-common-use-of-time-by-age-and-sex/
- Remind yourself of the (generic) hypotheses of a two way ANOVA--consider main effects and interactions.
- On the web page, identify two IVs and their categories (you do not have to use every category). If you are using time of day data, you would ideally use a block of time as a category in this hypothetical situation.
- Assume the DV is number of hours spent.
- Create a hypothesis for each of your main effects and the interaction using the variables you identified.

*Activity 3:*

**Understanding assumptions of two-way ANOVA**

Your book discussed the assumptions of two-way ANOVA. In this activity, you will apply this information.

- List the assumptions of two-way ANOVA. Is there anything different regarding the assumptions compared to one-way ANOVA?
- Go to the following website: http://flowingdata.com/2015/11/10/counting-the-hours/
- Scroll down to the first graph (How many hours did you spend working yesterday?).

- What do you think about the assumption of normality for this DV (IVs aside for now)? Specifically, do you think the assumption would be violated here?
- Read the short paragraph underneath that graph that starts with “Naturally, age…”
- Let’s say you were examining age as an IV. What impact might age have on homogeneity of variance and/or normality?

- Scroll down to the next chart (household activities).

- What SPSS statistic would you examine to determine if the assumption of homogeneity of variance was violated?
- What do you think about the assumption of normality for this DV? Specifically, do you think the assumption would be violated here?