Statistics
posted by Marc on .
The annual precipitation for one city is normally distributed with a mean of 72 inches and a standard deviation of 3.5 inches. In 95% of the years, the precipitation in this city is between___ and ___

From a normal distribution table, 97.5% probability corresponds to +1.96σ.
Thus μ±1.96σ corresponds to 95% of all years.
1.96σ = 1.96*3.5=6.86"
Therefore 95% of the years have precipitation between 72±6.86" 
n125, n236, s1 power 2=50, s2 2 power=72, m1=100. m2=105

n125, n236, s1 power 2=50, s2 2 power=72, m1=100. m2=105