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anonymous
 one year ago
The random variable Y is normally distributed with a mean of 470, and the value Y= 340 is at the 15th percentile of the distribution. Of the following, which is the best estimate of the standard deviation of the distribution?
A. 125
B. 135
C. 145
D. 155
E. 165
anonymous
 one year ago
The random variable Y is normally distributed with a mean of 470, and the value Y= 340 is at the 15th percentile of the distribution. Of the following, which is the best estimate of the standard deviation of the distribution? A. 125 B. 135 C. 145 D. 155 E. 165

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0dw:1436991107094:dw

phi
 one year ago
Best ResponseYou've already chosen the best response.1yes, and the 15th percentile is at about 1 std dev

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I'm so sorry i have to brb my mom needs help upstairs brb

phi
 one year ago
Best ResponseYou've already chosen the best response.11 std deviation means you are one standard deviation less than the mean the mean is 470 and 15th percentile is 340 the difference is about 1 standard deviation

phi
 one year ago
Best ResponseYou've already chosen the best response.1based on the choices, we have to be more accurate. based on your curve, 1 std deviation is at the 16th percentile (2+14= 16) and we are given the 15th percentile = 340 dw:1436991677454:dw

phi
 one year ago
Best ResponseYou've already chosen the best response.1the red line at 1 std dev is a little bit closer to the mean... so the difference should be a little bit less than 130

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Hey so how did you know that it was at the 16th percentile?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0oh wait nvm i see it now

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so if it's a little bit less than 130 it's 125?

phi
 one year ago
Best ResponseYou've already chosen the best response.1if you have a ztable, you could look up the z score for 0.15 (I think it's about 1.04) and then say 1.04*s= 130 s= 130/1.04 s= 125

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0hmmm ok i got it thank you !!
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