The weight of luggage that a randomly selected airline passenger brings onto a flight has a mean of 35 lbs and a standard deviation of 6 lbs. If a flight has 80 passengers, within what range would the average weight of their luggage fall with 95% certainty?

Question

The weight of luggage that a randomly selected airline passenger brings onto a flight has a mean of 35 lbs and a standard deviation of 6 lbs.  If a flight has 80 passengers, within what range would the average weight of their luggage fall with 95% certainty?

Damon · Answer

http://davidmlane.com/hyperstat/z_table.html

PsyDAG · Answer

To calculate it yourself:

95% = mean ± Z (SEm)

SEm = SD/√n

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability (±.025) and its Z score. Insert data into above equation.

Anonymous · Answer

23 to 47 pounds