SOLUTION: The average monthly cellular bill is $73. Suppose local monthly household call phone bills are normally distributed with a standard deviation of $11.35.
a. What is the probabili
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-> SOLUTION: The average monthly cellular bill is $73. Suppose local monthly household call phone bills are normally distributed with a standard deviation of $11.35.
a. What is the probabili
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Question 924488: The average monthly cellular bill is $73. Suppose local monthly household call phone bills are normally distributed with a standard deviation of $11.35.
a. What is the probability that a randomly selected monthly cell bill is less than $100
b. what is the probability that a randomly selected monthly cell bill is between $70 and $90. Answer by ewatrrr(24785) (Show Source):
You can put this solution on YOUR website! mean = 73, sd = 11.35,
Using the z-value to determine the Probability:
....
And...Using a TI calculator 0r similarly a Casio fx-115 ES plus
P( x < 100) = P( z < 27/11.35) = P( z < 2.3788) = normalcdf(-100, 2.3788) = .9913
......
For the normal distribution: Below: z = 0, z = ± 1, z= ±2 , z= ±3 are plotted. Area under the standard normal curve to the left of the particular z is P(z < than its value)
Note: z = 0 (x value: the mean) 50% of the area under the curve is to the left and 50% to the right
