Question 1105395
The mean of 10 people is 700, since one sums the mean.
The variance of 10 people is the sum of 10 variances, assuming independence and no covariance.
sigma ^2=900
sigma=sqrt (900)=30
Want to know the probability of finding something in a distribution of N(700, 30) exceeds 800
z>(800-700)/30=+3.33
That probability is 0.0004.