Question

According to a survey of the top 10 employers in a major city in the midwest, a worker spends an average of 413 minutes a day on the job. suppose the standard deviation is 26.8 minutes and the time spent is approximately a normal distribution. what are the times that approximately 95.44% of all workers will fall?

Answer 1

359.4 to 466.6 minutes. Looking at the problem, the value 95.44% leaps out as the percentage of data that falls within 2 standard deviations of the mean. So all you need to do is take the mean and subtract 2 standard deviations to get the lower bound, and take the mean and add 2 standard deviations to get the upper bound. Lower bound = 413 - 2 * 26.8 = 413 - 53.6 = 359.4 minutes Upper bound = 413 + 2 * 26.8 = 413 + 53.6 = 466.6 minutes So approximately 95.44% of all workers work from 359.4 to 466.6 minutes.