Find the indicated probabilities. If convenient, use technology to find the prob

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Find the indicated probabilities. If convenient, use technology to find the probabilities.

Utility Bills: The monthly utility bills in a city are normally distributed, with a mean of \$100 and a standard deviation of \$12. A utility bill is randomly selected.

(a) Find the probability that the utility bill is less than \$70
(b) Find the probability that the utility bill is between \$90 & \$120.
(c) Find the probability that the utility bill is more than \$140.

Mar 31st, 2015

a)  P(x<70)

mean = 100 sd = 12

z = (70 -100)/12 = -30/12 = -2.5

P(x<70)   =  0.0062

b)   z1 = (90-100 )/12 = -10/12 = -0.8333

z2 = 120-100 )/12 = 1.666

P(90 <x < 120 )  = 0.8944 - 0.0475 = 0.9515

c) P(x> 140) =

z = 140-100)/12 = 40/12 = 3.33

P(x>140) = 0.9996

all values of  probablilty comes from table

Mar 31st, 2015

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Mar 31st, 2015
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Mar 31st, 2015
Dec 10th, 2016
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