Assume that 8% of people are left-handed. We select 6 people at random. a) How many lefties do you expect? b) With what standard deviation? c) If we keep picking people until we find a lefty, how long do you expect it will take?

a) 0.48

b) 0.6645

c) 12.5

Step-by-step explanation:

For each person, there are only two possible outcomes. Either they are left-handed, or they are not. The probabilities of each person being left-handed are independent. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

The expected value of the binomial distribution is:

The standard deviation of the binomial distribution is:

The number of trials expected to find r sucesses is given by

In this problem we have that:

Assume that 8% of people are left-handed. We select 6 people at random.

This means that

a) How many lefties do you expect?

b) With what standard deviation?

c) If we keep picking people until we find a lefty, how long do you expect it will take?

Number of trials to find 1 success. So

597

step-by-step explanation:

560

step-by-step explanation:

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