High Level Statistics problems

Posted on 2014-03-14 09:48:00 in Statistics by CHAMMORROW

I"m having some issues with two of my stat homework problems. Any help would be appreciated.



First question:



An urn contains five red balls and five green balls. The toss of two fair coins will ultimately determine the final number of balls in the urn. If two heads are observed, then two red balls are removed from the urn. If one head is observed, then one red ball is removed from the urn. If no heads are observed, then no red balls are removed from the urn. Finally, three balls are randomly sampled from the urn. Find the probability of selecting exactly two red balls.





Second question:

A sample of apples was selected. The mean weight was 6.9 ounces and the standard deviation was 0.5 ounces. However, the farmer discovered that his weighing scale was not calibrated....to adjust the weight, the farmer must multiply each weight by 1.10, then add 0.4. After adjusting the weight of each apple, what are the new summary statistics?



Attempts:

For the first question, what I basically did was find the probability of getting two heads, and added that to the probability of selecting all green from the random sample. However, I feel like I'm leaving stuff out.



The second seems way too simple, I'm sure there is a trick to it. I'm sure that don't just multiply and add to the number and leave as it is. Maybe there is some type of conversion that I must do or something...



Anyway, help is appreciated.



Thanks

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