Weekend HW

This weekend, please complete the following in your textbook:

Page 127: 33, 34, 41abc, 42a

This assignment will give you some more practice finding percentages under the Normal curve! On Monday we'll look at our last type of problem for the unit, working backwards with the Normal model!

Do your homework! I'm checking!

Check the blog post from yesterday for help with normalcdf(!

Lastly, here are the book problems! (For the evens, the answers are in parentheses):

33.) Using N(1152, 84), the Normal model for weights of Angus steers, what percent of steers weigh...
a.) Over 1250 pounds?
b.) Under 1200 pounds?
c.) Between 1000 and 1100 pounds?

34.) Based on the Normal model N(100, 16) describing IQ scores, what percent of people's IQ's would you expect to be...
a.) Over 80? (about 89.4%)
b.) Under 90? (about 26.6%)
c.) Between 112 and 132? (about 20.4%)

41.) Assume the cholesterol levels of adult American women can be described by a Normal model with a mean of 188 mg/dL and a standard deviation of 24 mg/DL.
a.) Draw and label the Normal model.
b.) What % of adult women to you expect to have cholesterol levels over 200 mg/dL?
c.) What % of adult women do you expect to have cholesterol levels between 150 and 170 mg/dL?

42.) A tire manufacturer believes that the treadlife of its snow tires can be described by a Normal model with a mean of 32,000 miles and a standard deviation of 2500 miles.
a.) If you buy a set of these tires, would it be reasonable for you to hope they'll last 40,000 miles? Explain. (No answer for you here...consider how many standard deviations 40,000 miles falls from the mean...is this likely to occur? You can also consider what % of tires will last more than 40,000 miles? Is this likely to occur?)