How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters? We want 95% confidence that the sample mean is within 5 minutes of the population mean, and the population standard deviation is known to be 7 minutes.

Answer: 25 computers will be selected

Step-by-step explanation:

Where: Z - value at 95% confidence = 1.96; SD = Standard deviation = 10 minutes; N = Sample size; Margin error = 4 minutesSubstituting; 4 = 1.96*10/Sqrt (N) Sqrt (N) = (1.96*10) / 4 = 4.9N = 4.9^2 = 24.01 ≈ 25