Question

A certain experiment conducted was normally distributed. The mean value is 100.6725 and the standard deviation is 12.45. If the total population is 2000 (continuous variable), calculate the amount of population falling below an x-value of 120.75.

Answer 1

$$P(X<120.75)=P(Z<\dfrac{120.75-100.6725}{12.45})$$

$$\approx P(Z<1.61265)\approx0.94658978$$

$$0.94658978(2000)=1893$$

The amount of population falling below an x-value of 120.75 is 1893.