Here is a link to a data set concerning treatment groups A and B. Before performing a t-test to determine if the two groups are different, researchers must first ascertain if the variance in the two groups is the same using an F test. Indicate whether the hypothesis below is the null or alternate hypothesis for the F test. null The variance in group A is equal to the variance in group B Calculate the F statistic for this data set and report it in the box below, rounded to two decimal places. Use the formula =(1-(f.dist(F, df1,df2,true) in Excel to calculate the P value for the F statistic, and report it in the box below. Do not use the rounded value for F when calculating the P value. Use the value in the spreadsheet that has not been rounded. Based on this p value, would you recommend using a Student's t test or a Welch's t test to determine if the two treatment groups have different means? Enter either Student's or Welch's in the box below.
The hypotheses are:
Enter data in excel.
By using excel function, VAR.S(data range) the variances of two groups are:
The F test statistic is:
The degrees of freedom are:
By using excel function =1-F.DIST(B25,19,19,TRUE), the p-value is 0.119.
Since p-value = 0.119 > 0.05, we fail to reject the null hypothesis and we can conclude that the variance in group A is equal to the variance in group B.
Based on this p value, you would recommend using a Student's t test to determine if the two treatment groups have different means.
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