5728 > Macmillan Learning Suppose a researcher runs a t-test of the difference of two independent means. The samples are taken from populations of unknown variances that are not assumed to be equal. The sample sizes and standard deviations are summarized in the table. Group Sample size " = 22 8=47 Sample standard deviation 81-3.8742 82-5.7356 Use software to compute the Welch-Satterthwaite approximation of the degrees of freedom, df. You might find some software manuals useful. Give your answer precise to at least three decimal places. df- Attemp