Question

The Greater Metro Regional Transit Authority is the public transit agency for Deleware, and the surrounding suburbs of Metro County. The amount of time it takes for the Transit train to travel from City Hall to Park Avenue is normally distributed, taking an average of 15 minutes and a variance of 4.8. A random sample of 120 riders is selected from the population of all riders who take this route. Calculate the value of the standard error of the sample mean. Use only the appropriate formula and/or statistical table in your textbook to answer this question. Report your answer to 2 decimal places, using conventional rounding rules.

Answer 1

Solution :

Given that ,

mean = = 15

variance =  ² = 4.8

standard deviation = = ² = 4.8 = 2.19

n = 120

=   = 15

= / n = 2.19 / 120 = 0.20