Statistics – Discrete Probability Distributions – Review.
Complete this review, with work shown, before the test. You may use a 3x5 card of notes on the test.
All probability answers must be either a completely reduced fraction, a decimal rounded to 4 places or a percent rounded to 2
places. Round any other response to 2 decimal places.
Classify each as discrete or continuous.
1. The number of students in a classroom who are taller than 5 feet 10 inches.
2. The heights of students in a classroom.
For #3 – 4, use the discrete probability distribution at right:
3. Find the mean.
4. Find the standard deviation.
5. What are the conditions for random variable to be binomial?
6. What are the conditions for a random variable to be Poisson?
Determine if the experiment is a binomial experiment.
7. Surveying 50 people to see if they own a car.
8. Surveying 50 people to see how many cars they have owned.
A recent survey found that 37% of Americans owned a gun. A random survey of 300 Americans was conducted.
9. What is the random variable, X?
10. What is the mean of those who own a gun? Interpret the mean. (Hint: what does the mean tell us?)
11. What is the standard deviation of those who own a gun?
The number of insect fragments found in peanut butter follows a Poisson distribution with a mean of 0.3 insect
fragments per gram of peanut butter.
12. What is the random variable, X?
13. Find the mean for a 5 gram sample of peanut butter. Interpret the mean.
14. Find the standard deviation for a 5 gram sample of peanut butter.
The probability distribution shows the number of detentions a high school
student has.
15. What is the random variable, X?
16. What is the probability that a student has at
least 2 detentions?
17. What is the probability that a student has
fewer than 4 detentions?
18. Find the mean. Interpret the mean.
19. Find the standard deviation.
According to recent information, 65% of 16 – 18 year old males have been in a car accident. Suppose 12 males that
are 16 – 18 years old are randomly selected.
20. What is the random variable, X?
21. Find the probability that exactly 9 of them
have been in a car accident.
22. Find the probability that at least 9 of them
have been in a car accident.
23. Find the mean. Interpret the mean.
24. Find the standard deviation.
Between 11:00am and noon, the number of customers at a coffee cart occurs at the rate of 2.1 per minute.
25. What is the random variable, X?
26. Find the probability that exactly 3 customers
arrive between 11:35am and 11:40am.
27. Find the probability that at least 3 customers
arrive between 11:35am and 11:40am.
28. Find the mean. Interpret the mean.
29. Find the standard deviation.
30. Have you prepared a 3x5 card of notes for use on the test?