The average battery life of 2800 manufactured cell phones is recorded and normally distributed. the mean battery life is 14 hours with a standard deviation of .5 hours. find the number of phones who have a battery life in the 13 to 14 range.

1336 phones

Step-by-step explanation:

The average battery life of 2800 manufactured cell phones has a normal distribution.

The mean battery life is 14 hours, therefore: μ = 14 hours.

The standard deviation is 0.5 hours, therefore: σ = 0.5 hours.

To find the number of phones who have a battery life in the 13 to 14 range, we're going to ask for the help of a calculator. The probability of finding phones who have a battery life in the 13 to 14 range is: 0.4772. (See attached picture)

Therefore, the number of phones who have a battery life in the 13 to 14 range is: 0.4772×2800 = 1336,16 ≈ 1336 phones.

4.6875 pounds

step-by-step explanation:

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