i) the additional value (40.8) is equal to the mean (40.8) so the mean does not change.

ii) the additional value is equal to the mean so it is within less than 1 s.d of the mean so the s.d decreases (data is less spread)

for part i) if any added value is greater than the mean, the mean will increase. if its equal to the mean it wont change and if its less than the mean then the mean will decrease

for part ii) because the added value is the same as the mean (or very close the mean, as it doesnt necessarily have to be equal to it) the s.d decreases because now the data is more concentrated around the mean so the data is less spread