Originally Posted by
chrisc okay. my exam is approaching in a few days and I have one last question.
Let X1, X2, ... X7 be a set of seven independent random variables, each
having the uniform distribution of values from the [3, 6] interval (this is
called random independent sample of size 7 from this distribution).
(a) Find the expected value and standard deviation of their sum T ≡ X1 + X2 + ... + X7.
(b) What is the probability that more than three of these seven random
variables will have a value smaller than 1
3? Mr F says: The question is not clear to me. Is it meant to be 13, 1 or something else?
(c) Find the skewness and kurtosis of X1.
answers:
(a) E(x) = 7(6+3)/2 = 31.5
Var(x) = 7*[(6-3)^2]/2
standard deviation = 2.2913
(b) not sure
(c) would skewness be 0 since its uniform? what about kurtosis