To find the Mean and Standard Deviation

Question

Total amount of time (x, in minutes) spent commuting by the entire 240 residents of a housing area was recorded.

 

Given that total x = 10,980 and total ( x - µ )² = 23,191. Compute the mean and the standard deviation of commuting time. Give your answer to two decimal places

Answer 1

Total x = 10,980 and total (x-µ)² = 23,191, n=240.

So,  mean=x/240=10.980/240=45.75

Since (x-µ)² = 23,191, the the variance is

s²=(x-µ)²/n=23191/240

s=√(23191/240)=9.83