Question

Can someone help me verify if this is correct?

Gasoline usage for compact cars in Canada is a normal distribution with a mean of 33.3 km/l and with standard deviation of 7.3 km/L. Round your answers to one decimal place.

a) What percentage of compact cars obtains 20km/L or LESS?

z= x-mean/standard deviation
= 20-33.3/7.3
= 1.82 Km/L

(find percent through z-score table)

which becomes 0.0344 x 100
= 3.4 %

b) What percentage of compact cars obtains MORE than 40 km/L

z=40-33.3/7.3
= 0.92 km/L = 0.8212
= 1 - 0.8212
= 0.1788 x 100
= 17.9%

Question is, for question b, is it 1-0.8212 or 100-0.8212?

Answer 1

anyone?