Question

               Are you approximately normal?     

1. A study found that only 60% of all married women say that they would marry the same man “if they could do it all over again”. If we randomly sample 15 married women, find the probability that –

1. exactly twelve say they would marry the same man “if they could do it all over again”.

2. at least twelve say that they would marry the same man “if they could do it all over again”.

3. fewer than twelve say that they would marry the same man “if they could do it all over again”.

4. In a sample of 200 married women, would it be unusual to find 130 who say they would marry the same man “if they could do it all over again? Justify your answer.

Answer 1

for the last question:

Since we have considered X as a normal random variable So it is inconvenient to find the probability of P(X=130) because theoretically for a continuous random variable probability value at a single point is =0

So it is convenient to find the probability value of a certain range.

since we need 130, we have taken the range (125,135). You can choose any other range also of your own but it should contain 130.

Now here since the probability value 0.221 very small. so it would be unusual to find 130 who say they would marry the same man “if they could do it all over again".