121.(E)
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53
A vending machine is designed to dispense 8 ounces of coffee into a cup.
After a test that recorded the number of ounces of coffee in each of
1,000 cups dispensed by the vending machine, the 12 listed amounts,
in ounces, were selected from the data. If the 1,000 recorded amounts
have a mean of 8.1 ounces and a standard deviation of 0.3 ounce,
how many of the 12 listed amounts are within 1.5 standard deviations
of the mean?
(A) Four
(B) Six
(C) Nine
(D) Ten
(E) Eleven
想請問ㄧ下這題應該怎麼解
謝謝~
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