Can you please show how to do this by hand If needed standar

Can you please show how to do this by hand. If needed, standard normal probability table can be used:

http://www.math.unm.edu/OLD/courses/stat145/resources/normal.pdf

c. (6 pts.) What percent of American drink more than 2 cups of coffee daily? d. (6 pts.) What percent of Americans drink between 1.5 and 2 cups of coffee daily?

Solution

c.Find z=(x-)/=(2-1.66)/0.21=1.61

Thus, P(x>2)=1-P(x<2)=1-P(z<1.61)=1-0.9463=0.0537

d)=(1.5-1.66)/0.21=-0.76

P(1.5<X<2)=P(X<2)-P(X<1.5)

=P(z<1.61)-P(z<-0.76)

=0.9463-0.2236=0.7227