statistics
posted by Ab on .
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.
If you have a body weight of 89.3, what is your percentile score?

Here, Body Weight follows Normal (Mean = 98.3,SD=4.12)
Zscore of 89.3 = (89.3  98.3)/4.12 = 2.18
Now, P[Z<2.18]=0.0145
So, percentile score is 1.45% 
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.