1. Here are the data on the age of students that attending College.

age	19 and under	20-24	25-29	30-34	35+
	5910	5500	2155	1120	1908

What is the probability of a student's age between 20-24 years old?

2. As with most body measurements, height has a normal distribution. Basketball players are considered unusually tall if they are taller than 3 standard deviations above the mean height for men. Using the empirical rule, what is the probability that one randomly selected boy will be unusually tall?

3. In Ms. Curtis' statistics class, the mean score on the final exam is 73.8 points with a standard deviation of 9.4 points. Carl was enrolled in Ms. Curtis' class. His score on the final exam was 89.2. In Ms. Hutchings' statistics class, the mean score on the final exam is 80.25 points with a standard deviation of 8.63 points. Ray was enrolled in Ms. H's class. His score on the final exam was 89. Who performed better on the final exam relative to their classmates? Show what you used to make the comparison.

4. Assume the distribution of heights of adult men in the U.S. is normal with a mean of 172.5 cm and a standard deviation of 6.8 cm. Mark's height has a z-score of -1.2. What is Mark's height?

5. Two studies examined the relationship between heart disease and aspirin. Which study supports the conclusion that taking aspirin lowers the risk of heart attacks? Why?

Study 1: A researcher studies the medical records of 500 randomly selected patients. Based on the information in the records, he divides the patients into two groups: those given the recommendation to take an aspirin every day and those with no such recommendation. He reports the percentage of each group that developed heart disease.

Study 2: A researcher studies 500 patients who visited a regional hospital. He randomly assigns 250 patients to take aspirin every day and 250 to take a placebo that looks like aspirin. At the end of 5 years, he reports the percentage of each group that developed heart disease.