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probability

1. A city had an average of 2.6 lightning storms per month. What is the probability of at least 3 lightning storms during a month?

A. 12.26%
B. 21.76 %
C. 26.40%
D. 48.16%
E. none of the above

2. If the number of miles per gallon (mpg) achieved by cars of a particular model has a mean of 25 and a standard deviation of 2, what is the probability that, for a random sample of 20 such cars, the average mpg will be less than 24? Assume population distribution is normal.

A. 0.125
B. .1443
C. .2875
D .3026
E. none of the above

Solution Preview

1. A city had an average of 2.6 lightning storms per month. What is the probability of at least 3 lightning storms during a month?

A. 12.26%
B. 21.76 %
C. 26.40%
D. 48.16%
E. none of the above

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The answer is D) 48.16%.

Denote by X the number of lightning storms per month. We know that X follows ...

Solution Summary

It provides examples of calculating the probabilities when the samples follow Poisson distribution and normal distribution, respectively.

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