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The Problem |
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The average number of gallons of lemonade consumed by the football team during a game is 20, with a standard deviation of 3 gallons. Assume that the variable is normally distributed. When a game is played, find the probability of using a) Between 20 and
25 gallons |
a) Between 20 and 25 gallons
From the text of
the problem we know that 
=
20 and that 
=
3. The TI83/84 calculator provides a program to compute the probabilities
of normal distributions. We use the function:
Since we need the
area under the normal curve between 20 and 25, or 20 < x < 25, we
let 
=
20 and 
=
25.
From the calculator home screen, press 2nd VARS[DISTR], press 2 to select 2:normalcdf(. Enter 20,25,20,3) and then press ENTER. See the results below.
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Thus the P(20 < X < 25) = 0.4522
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