SOLUTION: Use the normal distribution to approximate the desired probability. A certain question on a test is answered correctly by 21.0 percent of the respondents. Estimate the probability
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Question 1064919: Use the normal distribution to approximate the desired probability. A certain question on a test is answered correctly by 21.0 percent of the respondents. Estimate the probability that among the next 146 responses there will be at most 42 correct answers. Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! the mean is np, here 146*0.21=30.66
the sd is sqrt (np(1-p)=sqrt (30.66*(0.79))=4.92
z < (42-30.66)/4.92=2.30
That probability is 0.9892 or 0.99.
