1. If n = 20 and p = .4, then the mean of the binomial distribution is A. 4.8 B.
ID: 2959689 • Letter: 1
Question
1. If n = 20 and p = .4, then the mean of the binomial distribution isA. 4.8
B. 12
C. .4
D. 8
2. In a study conducted for the State Department of Education, 30% of the teachers who left teaching did so because they were laid off. Assume that we randomly select 10 teachers who have recently left their profession. Find the probability that exactly 4 of them were laid off. A. .2001
B. .2668
C. .3000
D. .0090
3. A multiple-choice test has 30 questions and each one has five possible answers, of which one is correct. If all answers were guesses, find the probability of getting exactly four correct answers.
A. 0.8000
B. 0.1325
C. 0.0604
D. 0.2552
4. Two characteristics/assumptions of the Poisson distribution include:
A. Probability of success remains constant from trial to trial and the random variable of interest is continuous.
B. The event occurring in one interval is independent of the event occurring in any other non-overlapping interval, and the random variable of interest is continuous.
C. The event occurring in one interval is dependent of the event occurring in any other non-overlapping interval, and the random variable of interest is continuous.
D. The event occurring in one interval is independent of the event occurring in any other non-overlapping interval, and the random variable of interest is discrete.
5. A random variable is said to be discrete if A. Its outcomes are countable
B. It can be represented graphically
C. It can assume any real number within a given interval
D. The rules of probability apply
6. A company manufactures an appliance, gives a warranty and 95% of its appliances do not require repair
before the warranty expires. If an organization buys 10 of these appliances, calculate an interval that contains
95.44% of all the appliances that won't require repair.
A. [8.55 10.45]
B. [8.12 10.88]
C. [8.81 10.19]
D. [7.43 11.57]
7. Which of the following statements about the binomial distribution is not correct?
A. The experiment consists of n identical trials.
B. The random variable of interest is continuous.
C. The probability of success remains constant from trial to trial.
D. Trials are independent of each other.
E. Each trial results in a success or failure.
8. The equation for the variance of the binomial distribution is given by:
A.
B. np(1-p)
C.
D. np
9. It is known that 15% of all college freshmen at Ivey University leave after their first year. Calculate the
interval that contains 99.73% of the students who remain if we are looking at a random sample of 300 Ivey
University freshmen.
A. [236.45 273.55]
B. [26.45 63.55]
C. [38.82 51.18]
D. [110.25 369.75]
10. In the most recent election, 19% of all eligible college students voted. If a random sample of 20 students
were surveyed: Find the probability that exactly half voted in the election.
A. .4997
B. .0148
C. .0000
D. .0014
Explanation / Answer
Since this violates the terms of use policy...i will only answer the first one. You MUST only ask one question (with parts a, b, c...etc ok) per post. the formula for the expected value or mean for a binomial distribution is n*p hence... 20*0.4 = 8
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