1. Warm-Up On the driving range, Tiger Woods practices his golf swing with a particular club by hitting many, many balls. When Tiger hits his driver, the distance the ball travels follows a Normal distribution with mean 304 yards and standard deviation 8 yards. What percent of Tiger’s drives travel at least 290 yards? What percent of Tiger’s drives travel between 305 and 325 yards?

2. Homework Questions

3. Calculator Stuff

4. Examples  Z < 1.39 (use -100 as your lower bound)  Z > -2.15 (use 100 as your upper bound)  -0.56 < z < 1.81  Find the proportion of observations that are greater than 1.53

5. Use Table A backwards  Find the z-score for the 20 th percentile  (Find the closest thing to 0.20 on your table)  Find the z-score where 45% of all observations are greater than z.  (Remember…that means 55% below z)

6. Normalcdf(lower, upper, mean, std) Look at Tiger’s drives again. What proportion of Tiger’s dries traveled at least 290 yards? 2 nd VARS – normalcdf(290, 400, 304, 8) =.95994  pretty close to our answer from the table! What percent of Tiger’s drives travel between 305 and 325 yards? 2 nd VARS – normalcdf(305, 325, 304, 8) = ________  Little off – we rounded our z-scores from the table to two decimal places…

7. Let’s practice… Cholesterol levels above 240 mg/dl may require medical attention. The distribution is Norman with a mean of 170 mg/dl and a standard deviation of 30 mg/dl.  What percent of 14 year old boys have more than 240 mg/dl of cholesterol?  What percent have between 200 and 240 mg/dl?  What is the 1 st quartile of the distribution?

8. Invnorm(%, 0, 1)  This will tell you what the z-score is that corresponds to a certain percentage (area) to the left under the curve.  What z-score has 40% below it?  What z-score has 80% above it?

9. Homework  Pg 131 (41-54)