April 28, 2015

Homework Help: Statistics

Posted by Anonymous on Tuesday, March 19, 2013 at 6:09pm.

The weight of adult green sea urchins are normally distributed with a mean 52g and standard deviation 17.2g?
A. Find the percentage of adult green sea urchins with weighs between 50g and 60g

My answer/work: normalcdf (50, 60, 52, 17.2) = .225, 23%

B. Obtain the percentage of adult green sea urchins with weights above 40g

My answer/work: normalcdf (40, e99, 52, 17.2) = .757, 76%

C. Determine and interpret the 90% percentile for the weights

My answer/work: invnorm: .9, 0,1) =1.28
z-52 + (1.28)*(17.2)
z= 74.04%

I'm a little unsure if I got C correct. As for the rest I'm wondering if I did them correctly. If not, could someone lean me to the right direction? Thank you :)

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