Chapter 4 Review Questions Continuous or Discrete? 1. The number of students in a classroom 2. The total IQ of the students in a classroom. 3. The total amount of rainfall in a year, in inches. 4. The number of days per year that it rains. This is a probability distribution. (True or False?) 5. 6. 7. 8.

9. The mean of this distribution is: 10. The variance of this distribution is: 11. The standard deviation of this distribution is: In a recent study of Probability and Statistics students at King's Fork High School, it was found that 92.5% of the students had an average above D. Consider a sample of 50 students. 12. What is the mean of this sample? 13. What is the variance of this sample? 14. What is the standard deviation of this sample? It has been determined that 1 in five American adults lie on their income tax returns (made up number). In a random sample of 2350 American adults, what is the probability that: 15. exactly 500 of them lied on their tax return that year? 16. less than 500 of them lied on their tax return that year? 17. more than 500 of them lied on their tax return that year?

Last year, a certain football wide receiver caught at least one touchdown pass in 14 out of 16 games. If the player maintains that same rate, what is the probability that his first game with at least one touchdown reception this year happens: 18. in the second game? 19. before the third game? 20. after the second game? If the number of hits on a business's web site is 12 per minute, what is the probability that there are: 21. exactly 15 hits during any randomly selected minute? 22. more than 13 hits during any randomly selected minute? 23. less than 15 hits during any randomly selected minute?

A ball pit at the local McDonald's has 677 red balls, 876 blue balls, 712 green balls and 498 gold balls. If you randomly pull balls out, record their color and then replace them, what is the probability that the first gold ball you pull out happens: 24. on the fifth try? 25. after the third try? 26. before the third try? A researcher observes cars as they go by and records their colors. She observes 1458 cars, of which 256 are yellow. What is the probability that if she observes another 2500 cars, 27. at least 440 of them will be yellow? 28. at most 440 of them will be yellow? 29. between 430 and 445 (inclusive) will be yellow?