Can you help with this practice test on probability?

toni e

New member
I have a test tonight and have gone over my old test and am rereading chapters. I have this practice test. I don't have time to figure it all out and reread the chapters. If anyone can give answers and explanations so I can go over and study this, that would kind of rock. Ok here are the practice test questions. Thank you.


1. Determine whether the distribution is a probability distribution. If it is not state why.
X 1 3 5 7 9
P(X)

2. Construct a probability distribution for the data.
A box contains three $1 bills, two $5 bills, one $10 bill, and one $20 bill.

3. Given the following probability distribution, find the mean, variance, and standard deviation.

X 5 6 7 8 9
P(X) .2 .25 .38 .1 .07

4. A cash prize of $5000 is to be awarded by the Lincoln Fire Department. If 2500 tickets are sold at $5 each, find the expected value.

5. Compute the probability of X successes using the Table. n=6, X=3, p=0.3.

6. Compute the probability of X successes given n=25, X=8, and p=0.4.

7. A student takes a 10 question T-F exam and guesses on each question. Find the probability that he will get a passing grade. (Hint: What are ALL the passing grades?)

8. Find the mean, variance, and standard deviation for the value of n and p when the conditions are met for a binomial distribution.

n=50 p =0.3

9. A survey found that 25% of pet owners had their pets bathed professionally rather than doing it themselves. If 18 pet owners are randomly selected, find the probability that exactly 5 people have their pets bathed professionally.

10. If a beauty operator estimates that 30% of her customers want a permanent on any given day. What is the probability that out of her next 15 customers more than 5 want a permanent?
 
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