Problems with ttest quiz

[ghost]

Im not sure why I keep getting this wrong, I entered the answer in positive form (which is what the formula gave me), and I received no credit for the question. I may have used the other formula since there are two in the slides but there shouldn't be any difference because the question explicitly says to enter the answer in positive form.

[AlbertAini]

happened to me also. I just ended up redoing it and putting it as negative.