# nice intervalls

Hey guys outthere, can you help me? The probability for any random variable to be in the three sigma intervall around its mean is generally (please choose most appropriate answer): a) about 68 % b) between 84 % and 99,5 % c) about 99 % d) bigger than 88,888 %.

Well, the question is very awkward. They want the answer to be d) because Chebyshev says that for any r.v., the probability it is within k*sigma of its mean is at least 1-1/k^2. That word “generally” is completely inappropriate there.

Thanks for the anwswer. But why is generally wrong?

Because Chebyshev’s inequality isn’t something that is “generally” true anymore than the it is “generally” true that for a circle the ratio of circumference to diameter is Pi.

sorry Joey, I didn’t get it.

OK The following sentence is true: “The probability for any random variable to be in the three sigma intervall around its mean is ALWAYS bigger than 88,888 %.” That makes the sentence “The probability for any random variable to be in the three sigma intervall around its mean is GENERALLY bigger than 88,888 %.” kinda true in the way that Maratikus would probably like to argue either side of just for the sport of it.

Thank you. Sounds philosophical. I thought that general and always is mostly the same.

Try telling your wife “Honey, I will generally love you”

JoeyDVivre Wrote: ------------------------------------------------------- > Try telling your wife “Honey, I will generally > love you” lol

JoeyDVivre Wrote: ------------------------------------------------------- > Try telling your wife “Honey, I will generally > love you” +1

this forum is getting bloodier by the minute…

liaaba Wrote: ------------------------------------------------------- > this forum is getting bloodier by the minute… Its coming ever closer to that time of month again…

got it, I should improve my english