1. Math 21 Midterm Review
Part 2: Chapters 5-7

2. 13) In a drug trial there are 8 participants
13) In a drug trial there are 8 participants. In how many different ways can three of the participants be selected to receive a placebo?
Selecting r out of n
No repetition
Does order of selection matter?

3. 14) A sprint race has 12 runners in it
14) A sprint race has 12 runners in it. In how many different ways can the runners finish first, second, third, and fourth?
Selecting r out of n
No repetition
Does order of selection matter?

4. 15) A pizza restaurant has 5 different crusts available and 11 pizza toppings. Assuming that a customer cannot select the same topping more than once, in how many different ways can a customer order a 4-topping pizza?

5. 16) The probability that a registered voter is female is 0. 5
16) The probability that a registered voter is female is 0.5. The probability that a registered voter is registered as an independent is 0.3. The probability that a registered voter is female and is registered as an independent is 0.2. a) Find the probability that a registered voter is female or independent.

6. 16) The probability that a registered voter is female is 0. 5
16) The probability that a registered voter is female is 0.5. The probability that a registered voter is registered as an independent is 0.3. The probability that a registered voter is female and is registered as an independent is 0.2. b) If a randomly selected voter is a female, find the probability that she is registered as an independent.

7. 17) Seven males and five females are to be interviewed for a job as a community college instructor. The top four candidates are sent forward to the president for a second interview. If all the candidates are equally qualified, find the probability that four females get a second interview.

8. 18) A recent report stated that 84% of all elementary school teachers have a computer at home. If 12 elementary school teachers are selected at random, find the probability that 8 of them have a computer at home. n x
Success p

9. 19) Sixty percent of the students at a particular community college are female. If 13 students at that community college are selected at random, find the probability that between 5 and 10 students, inclusive, are female. n x
Success p

10. 20) Ten percent of the adults in a certain city hold a bachelor’s or higher degree. If 5 adults from this city are selected at random, find the probability that at least 3 do not have a bachelor’s or higher degree. n x
Success p

11. 21) On a typical day at UC Santa Barbara there are 2
21) On a typical day at UC Santa Barbara there are 2.9 bike crashes per day. Find the probability that there will be 2 bike crashes on that campus today. l t
Mean x

12. 22) On an average day there are 2 students absent from my math 21 class. Find the probability that 3 or more students are absent from my math 21 today. l t
Mean x

13. 23) On average, the Fresno Grizzlies score 4. 7 runs per game
23) On average, the Fresno Grizzlies score 4.7 runs per game. Find the probability that the team scores exactly 11 runs in the next two games. l t
Mean x

14. 24) The weights of salmon fillets at a fish market follow a normal distribution with a mean of 21 ounces and a standard deviation of 2.3 ounces. Find the probability that an individual salmon fillet will weigh more than 25 ounces. m s x

15. 25) IQ scores are approximately normally distributed with a mean of 100 points, and a standard deviation of 15 points. Find the probability that a person has an IQ of 110 or lower. m s x

16. 26) The heights of adult males are normally distributed with a mean of 69.0 inches and a standard deviation of 2.8 inches. What height separates the shortest 15% of adult males from the rest? m s
Tail %

17. 28) Use a QQ Plot to determine whether the following data come from a population that is normally distributed. Times, in seconds, for greyhounds to run a 5/16-mile race