Assume the body weight of healthy fifth graders is normally distributed with a mean of 98.3 lbs and a standard deviation of 4.12 lbs.

Question

If you have a body weight of 89.3, what is your percentile score?

Answer 1

Here, Body Weight follows Normal (Mean = 98.3,SD=4.12)

Z-score of 89.3 = (89.3 - 98.3)/4.12 = -2.18

Now, P[Z<-2.18]=0.0145

So, percentile score is 1.45%

Answer 2

I am having a difficult time figuring the last portion of this equation. How do we get P[Z<-2.18] = 0.0145 to get 1.45%. I have worked it out every way possible but answer is not coming up as yours.