Short answers

8. A researcher want to compare marks from two units, ETF2121 and ETF2020. She selects 30 students who attended both ETF2121 and ETF2020 and obtains their marks for each. Let X1, s1, n and X2, $2, n2 denote the mean, standard deviation, and sample size of sample 1 (ETF2121) and sample 2 (ETF2020). She computes a statistic using the following formula T = X1 - X2 + n1 12 and finds that T = 1.23. From this she concludes that the marks of ETF2121 is not statistical significantly different from ETF2020. Is her conclusion valid