SOLUTION: According to one​ poll, 45​% of households in a certain region still had landline phone service. Suppose a random sample of 50 households from the region is taken. Complete par

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Question 1175347: According to one​ poll, 45​% of households in a certain region still had landline phone service. Suppose a random sample of 50 households from the region is taken. Complete parts​ (a) through​ (d) below. a. Find the probability that exactly 20 of the households sampled still have a landline.
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
 p-hat = 20/50 = .40
z+=blue+%28x+-+mu%29%2Fsqrt%28blue%28p%281-p%29%2Fn%29%29
   z = %28.40-.45%29%2Fsqrt%28blue%28.45%2A.55%29%2F50%29%29 = -.7107
 P(z ≤ -.7107)= .2386
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