Pre-Calculus Pre-AP
Probability
Bernoulli Trials WS
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Period: ________ Date: ___________________________
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Suppose that a family has 5 children. Also, suppose that the probability of having a girl is . Find the probability that
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the family has the following children.
1.
2.
3.
4.
5.
6.
7.
8.
Exactly 2 girls and 3 boys
Exactly 3 girls and 2 boys
No girls
No boys
At least 4 girls
At least 3 boys
No more than 3 boys
No more than 4 girls
A die is rolled 12 times. Find the probabilities of rolling the following.
9. Exactly 12 ones
10. Exactly 6 ones
11. Exactly 1 one
12. Exactly 2 ones
13. No more than 3 ones
14. No more than 1 one
A coin is tossed 5 times. Find the probabilities of getting the following.
15. All heads
16. Exactly 3 heads
17. No more than 3 heads
18. At leads 3 heads
19. How do you identify a problem that involve a binomial experiment?
20. How is Pascal’s triangle used to find probabilities?
According to a recent article in a business publication, only 20% of the population of the United States has never had
a Big Burg hamburger at a major fast-food chain. Assume independence and find the probabilities that a random
sample of 10 people produces the following data.
21. Exactly 2 people have never had a Big Burg
22. Exactly 5 people have never had a Big Burg
23. Three people or fewer have never had a Big Burg
24. Four people or more have had a Big Burg
The insurance industry has found that the probability is .9 that a life insurance applicant will qualify at the regular
rates. Find the probability that of the next 10 applicants for life insurance, the following number will qualify at the
regular rates.
25. Exactly 10
26. Exactly 9
27. At least 9
28. Less than 8
A company gives prospective workers a 6-question, multiple choice test. Each question has 5 possible answers. Find
the probabilities of getting the following results by chance.
29. Exactly 2 correct answer
30. No correct answers
31. At least 4 correct answers
32. No more than 3 correct answers
33. Over the last decade, 10% of all clients of J.K. Loss & Company have lost their life savings. Suppose a sample of 3
clients of the firm is chosen. Assuming independence, find the probability that exactly 1 of the 3 clients will lose
everything.
A factory tests a random sample of 20 transistors for defective transistors. The probability that a particular transistor
will be defective has been established by past experience as .05.
34. What is the probability that there are no defective transistors in the sample?
35. What is the probability that the number of defective transistors in the sample is at most 2?
A new drug cures 70% of the people taking it. Suppose 20 people take the drug; find the probabilities of the following.
36. Exactly 18 people are cured
37. Exactly 17 people are cured
38. At least 17 people are cured
39. At least 18 people are cured