According to the Bureau of Labor Statistics, 7.1% of the labor force was recently unemployed. A random sample of 100 employable adults was selected. Using the normal approximation to the binomial distribution, what is the probability that fewer than 11 people from this sample are unemployed?

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Quizplus · Accepted Answer

Using the normal approximation to the binomial distribution, with n=100 and p=0.071, the mean is np=7.1 and the standard deviation is sqrt(np(1-p))=2.57. We find the z-score for 10.5 (continuity correction) and use the standard normal distribution to find the probability.