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anonymous
 4 years ago
Can you see if you can get an answer to this question?
X is distributed normally, P(X>59.1)=0.0218 and P(X>29.2)=0.9345.
Find the mean and standard deviation of the distribution to 3 s.f
anonymous
 4 years ago
Can you see if you can get an answer to this question? X is distributed normally, P(X>59.1)=0.0218 and P(X>29.2)=0.9345. Find the mean and standard deviation of the distribution to 3 s.f

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anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Because its P(X>a) you need to do 1P to get correct Zvalues Z1 = (59.1 m)/s Z2 = (29.2 m)/s you will have to solve system of 2 equations using substitution

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Yes, but is there such thing as P(X>29.2)=0.9345?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0no, probabilities must be within 0 and 1

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0i get m = 42 s = 8.47

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0that's right.. How did you get that?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0by solving the system of equations you should get Z1 = 2.018 Z2 = 1.51 right

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Wait, how did you get Z2?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0which is 0.0655... But I don't have that value on my distribution table?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0just round it to the closest one.. 0.066 if you have excel, use "Norminv" function, it will give you the zvalues as well

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0It starts at 0.5? And I can't use excel in my exam, so... how can I find the value otherwise?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0it doesn't show probabilities less than 0.5 ??

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0ok look up .9345 and flip the sign of the zvalue

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0yeah, you can do that because the distribution is symmetric

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.0Ah Ok. Thanks... So from there, what are the two equations which result?

anonymous
 4 years ago
Best ResponseYou've already chosen the best response.02.018 = (59.1 m)/s 1.51 = (29.2 m)/s solve one for s > s = (59.1m)/2.018 plug that into 2nd equation to find m
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