Thread: advanced stats

i need help with a couple of questions:

Suppose the generator is asked to produce 10,000 numbers between 20 and 25. Find the expected value and the standard deviation of this data?


Brand A sells for $12, B for $25, C$40. Of the USBs sold: 65% from Brand A, 25% from B and 10% from C. The profit for the company is 40% of the retail value, so y=4x for the rv for the profit. Find the expected value and the variance for the profit.

Hey lrocha91.

The first thing you need to do is assign a distribution to the numbers and since they are "generated" I'm assuming a uniform distribution: is this correct?

Hint: Can you calculate the expectation and sample variance of the data?

i'm assuming you can. but i have no clue how to approach and continue these questions. i've just gone in circles.

What is the expectation of a uniform distribution U(20,25)?

Hint: The PDF function is f(x) = 1/5 and the expectation is E[X] = Integral (20 to 25) x*(1/5)dx.