SOLUTION: The time it takes to travel from home to the office is normally distributed with {{{mu= 25}}} minutes and {{{sigma = 5}}} minutes. a. What is the probability the trip takes more

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Question 223174: The time it takes to travel from home to the office is normally distributed with mu=+25 minutes and sigma+=+5 minutes.
a. What is the probability the trip takes more than 20 minutes?
b. What is the probability the trip takes less than 15 minutes.
c. What is the probability the trip takes between 30 and 35 minutes?
d. What is the probability the trip takes more than 40 minutes?
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
The time it takes to travel from home to the office is normally distributed with mu=+25 minutes and sigma+=+5 minutes.
a. What is the probability the trip takes more than 20 minutes?

        On your TI-83 or TI-84 calculator:

        1.  Press CLEAR
        2.  Press 2ND 
        3.  Press VARS 
        4.  Press 2
        6.  You see normalcdf( 
        7.  After that type in:  20,999999999,25,5) so that what you see
            is this 
            
            normalcdf(20,999
            999999,25,5)

        8.  Press ENTER
        9.  Read the answer .8413447404

b. What is the probability the trip takes less than 15 minutes.

        1.  Press CLEAR
        2.  Press 2ND 
        3.  Press VARS 
        4.  Press 2
        6.  You see normalcdf( 
        7.  After that type in:  -999999999,15,25,5) so that what you see
            is this: 
            
            normalcdf(-99999
            9999,15,25,5)
            
            Caution: be sure that the "-" is the NEGATIVE sign on the
            very bottom right button, that looks liks this (-), and NOT
            the minus sign above the + button. 
               
        8.  Press ENTER
        9.  Read the answer .022750062

c. What is the probability the trip takes between 30 and 35 minutes?

     1.  Press CLEAR
        2.  Press 2ND 
        3.  Press VARS 
        4.  Press 2
        6.  You see normalcdf( 
        7.  After that type in:  30,35,25,5) so that what you see
            is this 
            
            normalcdf(30,35,
            25,5)

        8.  Press ENTER
        9.  Read the answer .1359051975

d. What is the probability the trip takes more than 40 minutes?


        1.  Press CLEAR
        2.  Press 2ND 
        3.  Press VARS 
        4.  Press 2
        6.  You see normalcdf( 
        7.  After that type in:  40,999999999,25,5) so that 
            what you see is this 
            
            normalcdf(40,999
            999999,25,5)

        8.  Press ENTER
        9.  Read the answer .0013499672  

If you're supposed to use tables and not a calculator, then
post again telling us whether you have the kind of tables
with both negative and positive z-scores or whether you have
the kind with onl;y positive z-scores.

Edwin