The Following Data Show the Results from an Independent-Measures Study

Essay

The following data show the results from an independent-measures study comparing two treatments.
a. Compute the independent-measures t statistic for these data.
b. Compute the percentage of variance explained by the treatment effect (r²).
b.)​Treatment $$\begin{array} { l l } \mathrm { I } & \mathrm { II } \\1 & 6 \\6 & 13 \\6 & 12 \\3 & 9 \\\hline \mathrm { M } = 4 & \mathrm { M } = 10 \\\mathrm { SS } = 18 & \mathrm { SS } = 30\end{array}$$
c. Convert the data into a form suitable for calculating the point-biserial correlation, and compute the correlation. (You should find that squaring the point-biserial correlation will produce the same r² value that you obtained in part