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AnimalLover8
 one year ago
The time required to finish a test in normally distributed with a mean of 80 minutes and a standard
deviation of 15 minutes. What is the probability that a student chosen at random will finish the test in more
than 95 minutes?
AnimalLover8
 one year ago
The time required to finish a test in normally distributed with a mean of 80 minutes and a standard deviation of 15 minutes. What is the probability that a student chosen at random will finish the test in more than 95 minutes?

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jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1Do you have a TI calculator?

AnimalLover8
 one year ago
Best ResponseYou've already chosen the best response.0No, if I did I would be able to do many more questions.

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1ok we'll use a table then

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1first convert the raw score x = 95 to a zscore use the formula z = (xmu)/sigma

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1in this case, mu = 80 and sigma = 15

AnimalLover8
 one year ago
Best ResponseYou've already chosen the best response.0What is the "raw score"?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1x = 95 is the raw score

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1it's the score on the test the zscore is the transformed score to the standard normal distribution

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1z = (xmu)/sigma z = (9580)/15 z = ???

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1Now use a table like this one https://www.stat.tamu.edu/~lzhou/stat302/standardnormaltable.pdf locate the row that starts with `1.0` and find the column that has `.00` at the top the intersection of this row and column has the number ______ (fill in the blank)

AnimalLover8
 one year ago
Best ResponseYou've already chosen the best response.0I don't understand what this number actually is.

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1this number represents the probability of getting a zscore less than 1.00 in notation form, we say `P(Z < 1.00) = 0.84134` so there's approx a 84.134 % of getting a zscore less than 1.00 in other words, there is a 84.134 % chance of getting a test score less than 95

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1subtract 0.84134 from 1 to get the probability of getting a score larger than z = 1 or x = 95

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1compute 1  0.84134

AnimalLover8
 one year ago
Best ResponseYou've already chosen the best response.0Wait so how do you get the probability from there?

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.11  0.84134 = 0.15866

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.10.15866 = 15.866% which rounds to 16%

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1we have some normal curve dw:1440808310147:dw

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1dw:1440808329487:dw

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1dw:1440808367344:dw

AnimalLover8
 one year ago
Best ResponseYou've already chosen the best response.0Yeah. :) Thank you so much!

jim_thompson5910
 one year ago
Best ResponseYou've already chosen the best response.1I'm glad that everything is making sense now

AnimalLover8
 one year ago
Best ResponseYou've already chosen the best response.0Me too, I usually pick things up very quickly, but I just couldn't hack this question. :)
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