First, take a subset of the data corresponding to the number of letters in your first name. For simplicity, you can delete all the other rows of data below. For the rows left, calculate the mean value using the AVERAGE function in excel. To do this, type "=AVERAGE(" into the cell next to "mean", and then highlight the cells above for which you want to compute the average. List the mean for your treatment and control groups in their corresponding columns, in the row labeled "mean