Answer
a) .41 + .21 = .62
b) .41 + .21 + .03 = .65
c) .34 + .01 = .35
Work Step by Step
The whole area underneath the curve is 1. The decimal points shown are the areas underneath set curve and they must all add up to 1. Similar to probability. So to find the probability of having a parasite with said length we just need to add up those probabilities.
a) For this we want anything between 20 and 30. So therefore we add .41 as that is from 20-25 μm and .21 as that is from 25-30 μm.
b) For b we want anything greater than 20 so we need everything from 20-35 μm. This is .41+.21+.003.
c) For c we want everything under 20 so we add .01 + .34.
