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 3 minutes of the population mean, and the population standard deviation is known to be 12 minutes.

61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.                

Step-by-step explanation:

Given : We want 95% confidence that the sample mean is within 3 minutes of the population mean, and the population standard deviation is known to be 12 minutes.

To find : How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters?

Solution :

At 95% confidence the z-value is z=1.96

The sample mean is within 3 minutes of the population mean i.e. margin of error is E=3 minutes

The population standard deviation is s=12 minutes

n is the number of sample

The formula of margin of error is given by,

Substitute the value in the formula,

Squaring both side,

Therefore, 61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.

6e14 is the answer.