# In practice exam 2 question 3 we find DIFFERENT standard deviations?

your solution sir indicates a value of 887.44. But i find in both standard deviations this number: 881,87!

All the other elements are correct though. mean becomes 0. SD becomes 1. exactly because the SDs are equal. But they are equal at 881,87, not, 887.44 for some reason.

Also you can please better explain the 2,7 part being the closest? Thanks in advance.

Hi, This is mainly for others. You have calulated the population standard deviation here in stead of the sample standard deviation. Granted there isnt enough info to suggest that this dataset is a sample instead of population. In excel make sure to use STDEV.S to calculate (compare to STDEV.P). STDEV.S > STDEV.P as we divide sample mean by n-1 and take square root to get sample standard deviation. The data/answer is correct