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Exercise

Null hypothesis testing

Null hypothesis testing uses p-values to see if a variable is "significantly" different from zero. Recently, the abuse and overuse of null hypothesis testing and p-values has caused the American Statistical Association to issue a statement about the use of p-values.

Because of criticisms such as these and other numerical challenges, Doug Bates (the creator of the lme4 package) does not include p-values as part of his package. However, you may still want to estimate p-values, because p-values are still commonly used. Several packages exist, including the lmerTest package.

lmerTest uses the same lmer() syntax as the lme4 package, but includes different outputs. During this exercise, you will fit a lmer() model using lmerTest and lme4.

Instructions 1/2
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  • Load the lmerTest package, which will also load the lme4 package.
  • Build a lmer() model using only the lme4 package. In R, this is done with lme4::lmer().
  • Build the same lmer() but use the lmerTest package.
  • Look at each model's summary.