11.2 t-test for a difference of independent sample means

I had conceived of using hula hoops with a goal of recording the number of rotations attainable in a minute. After data would have been gathered, a study of whether a gender difference exists for hooping would have been run. A hidden variable experiment of a sort. But the El Niño spring dry weather returned with brilliant sunshine. The weather convinced me to rerun the paper aircraft experiment using the darts.

The real variable, however, was the absence of wind. That absence plus the darts distance capabilities ensured a strongly significant difference. 

The second floor balcony from which the aircraft are launched. Klara, Vincent, Jeffrin, and Kenygie.


The p-value was surprising. The effect size is very large with a Cohen's d value of 1.43

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