Ap Statistics Test 3

Test 8A

A P Statistics

Name:

Directions: Work on these sheets. A random digit table is attached.
Part 1: Multiple Choice. Circle the letter corresponding to the best answer.

1. In a large population of college students, 20% of the students have experienced feelings of math anxiety. If you take a random sample of 10 students from this population, the probability that exactly 2 students have experienced math anxiety is
(a) 0.3020
(b) 0.2634
(c) 0.20 13
(d) 0.5
(4 1
(f) None of the above
2. Refer to the previous problem. The standard deviation of the number of students in the sample who have experienced math anxiety is
(a) 0.0160
(b) 1.265
(c) 0.2530
(d) 1
(e) .2070
3. In a certain large population, 40% of households have a total annual income of $70,000. A
What is the probability that 2 or more of the households in the survey have an annual income of over $70,000?
(a) 0.3456
(b) 0.4000
(c) 0.5000
(d) 0.5248
(e) The answer cannot be computed from the information given.

4. A factory makes silicon chips for use in computers. It is known that about 90% of the chips meet specifications. Every hour a sample of 18 chips is selected at random for testing. Assume a binomial distribution is valid. Suppose we collect a large number of these samples of 18 chips and determine the number meeting specifications in each sample. What is the approximate mean of the number of chips meeting specifications?
(a) 16.20
(b) 1.62
(c) 4.02
(d) 16.00
(e) The answer cannot be computed from the information given.

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