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: 5 points

: 5 points

10 points

A machine is designed to fill 16-ounce bottles of shampoo. When the machine is working properly, the amount poured into the bottles follows a normal distribution with mean 16.05 ounces with a standard deviation of .4 ounces. 

If four bottles are randomly selected each hour and the number of ounces in each bottle is measured, then 95% of the means calculated should occur in what interval? 

Hint: the standard deviation rule says that 95% of the observations are within how many standard deviations away from the mean?