0.1 Review exercises (ch 3-13)  (Page 2/12)

12. Find the probability that a student is Asian or Male.

13. Find the probability that a student is Black given that the student is female.

14. A sample of pounds lost, in a certain month, by individual members of a weight reducing clinic produced the following statistics:

• Mean = 5 lbs.
• Median = 4.5 lbs.
• Mode = 4 lbs.
• Standard deviation = 3.8 lbs.
• First quartile = 2 lbs.
• Third quartile = 8.5 lbs.

1. One fourth of the members lost exactly two pounds.
2. The middle fifty percent of the members lost from two to 8.5 lbs.
3. Most people lost 3.5 to 4.5 lbs.
4. All of the choices above are correct.

15. What does it mean when a data set has a standard deviation equal to zero?

1. All values of the data appear with the same frequency.
2. The mean of the data is also zero.
3. All of the data have the same value.
4. There are no data to begin with.

16. The statement that describe the illustration is:

1. the mean is equal to the median.
2. There is no first quartile.
3. The lowest data value is the median.
4. The median equals $\frac{Q_1+Q_3}{2}$ .

17. According to a recent article in the San Jose Mercury News the average number of babies born with significant hearing loss (deafness) is approximately 2 per 1000 babies in a healthy baby nursery. The number climbs to an average of 30 per 1000 babies in an intensive care nursery. Suppose that 1,000 babies from healthy baby nurseries were randomly surveyed. Find the probability that exactly two babies were born deaf.

18. A “friend” offers you the following “deal.” For a $10 fee, you may pick an envelope from a box containing 100 seemingly identical envelopes. However, each envelope contains a coupon for a free gift.

• Ten of the coupons are for a free gift worth $6.
• Eighty of the coupons are for a free gift worth $8.
• Six of the coupons are for a free gift worth $12.
• Four of the coupons are for a free gift worth $40.

Based upon the financial gain or loss over the long run, should you play the game?

1. Yes, I expect to come out ahead in money.
2. No, I expect to come out behind in money.
3. It doesn’t matter. I expect to break even.

Use the following information to answer the next four exercises: Recently, a nurse commented that when a patient calls the medical advice line claiming to have the flu, the chance that he/she truly has the flu (and not just a nasty cold) is only about 4%. Of the next 25 patients calling in claiming to have the flu, we are interested in how many actually have the flu.

19. Define the random variable and list its possible values.

20. State the distribution of X .

21. Find the probability that at least four of the 25 patients actually have the flu.

22. On average, for every 25 patients calling in, how many do you expect to have the flu?

Use the following information to answer the next two exercises: Different types of writing can sometimes be distinguished by the number of letters in the words used. A student interested in this fact wants to study the number of letters of words used by Tom Clancy in his novels. She opens a Clancy novel at random and records the number of letters of the first 250 words on the page.