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The following questions are taken from old practice exams found under PRACTICE EXAMS under ASSIGNMENTS. SOLUTIONS/ANSWERS TO THESE CAN BE FOUND UNDER PRACTICE EXAMS UNDER ASSIGNMENTS.

PRACTICE EXAM IIA 1 THRU 6, 8, 9, 14

1. The standard normal distribution has mean ______ and standard dev. ______.

2. Let z be a random variable with a standard normal distribution. Find P(-2 < z < 1.2).

3. The life of a turntable is normally distributed with mean 2.3 years and std dev. .4 year. Find the probability that a turntable breaks down within 2 years. ( 4 decimal places)

4. For a random variable that is normally distributed, with mean 80 and standard deviation ...view middle of the document...

exactly 2 get sick during the semester

b. At most 12 get sick during the semester (Answers to 3 decimal places)

2. Can the following function serve as a probability distribution of a random variable?

f(x) = 1/9 , x = 1, 2, 3, 4, 5, 6 (Y/N, and state reason why or why not)

3. Find the mean and standard deviation of the distributions of the following binomial random variable: the number of people among 100 who attend a concert, where p(attending) is .4.

4. Find the area under the standard normal curve which lies:

a. to the right of z = - .33

b. to the left of z = 1.06

c. between z = - .2 and z = 1.0

5. Find the value of z for which the area under the normal curve to the right of z is equal to

a. .76

b. .33

6. A random variable has a normal distribution with mean 44.2 and std dev 4.2 What is the probability of the random variable taking on a value between 47.8 and 55.1 ?

8. X -1 0 1 2

p(x) .1 .3 .2 .4

a. Calculate E(X-1) , E(6X-10)

b. Calculate Var(X) , Standard deviation (X)

c. Find P(X>0)

d. Find P(X greater than or equal to 1)

11. An automobile lasts on average 14 years with a std deviation of 2.2 years. Find the probability that a random sample of 60 of these autos will last on the average at least 13.5 years.

13. The probability is .4 that a question is answered correctly on an examination . Find the prob. that at least 14 out of 45 questions are answered correctly. (Normal...

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