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  3. Causal Inference with R - Experiments

Exercise

Common Issues in Interpretation II: Non-Normal Distributions (2)

There are many ways to deal with data that are multimodal in order to get them to be normally distributed. A common strategy for dealing with data that are ordered on a Likert scale is to collapse the response options. This is feasible if we assume that it is not important to differentiate the degree of positive or negative feelings for a restaurant. In this case, we will want to collapse response options 1 and 2 into a single response option to represent negative opinions, and 4 and 5 into a single response option to represent positive opinions.

Instructions

100 XP
  • 1) Create a new variable that collapses Reviews_After variable into 3 points: negative, ambivalent, and positive.
  • 2) Run a t-test that compares the treatment and control with the new ratings scale, and look at the p value.