SOLUTION: The length of elephant pregnancies from conception to birth varies according to a distribution that is approximately normal with mean 525 days and standard deviation 30 days. What

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Question 1179110: The length of elephant pregnancies from conception to birth varies according to a distribution that is approximately normal with mean 525 days and standard deviation 30 days. What percent of pregnancies last between 510 and 540 days?
Can you also write the formula in addition to the answer? Thank You
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
distribution approximately normal with µ = 525 and σ = 30
The area in Red P(510 < x < 540) can be found by calculating P(x ≤ 540) - P(x ≤ 510)
.
Using z -values, |z+=blue+%28x+-+mu%29%2Fblue%28sigma%29
knowing P is always the area to the left of the z-value: 
 P(z ≤ (15)/30) - P( z ≤ (-15)/30)  Use tables to determine P(Z-values) for subtraction:
0r
 Using a TI calculator 0r similarly a Casio fx-115 ES plus
Takes seconds:
P(510 < x < 540) = normalcdf(510,540,525,30) = .3829

Important You are comfortable using Your calculator.  
Wish You the Best in your Studies.
Standard Normal Curve with various z-values