Count the total number of objects. That is the denominator, which goes under the line. Then, only count the stars. That number is the numerator, which goes on top.
Looks like a badly encoded/decoded symbol. It's supposed to be a minus sign, so you're asked to find the expectation of 2<em>X </em>² - <em>Y</em>.
If you don't know how <em>X</em> or <em>Y</em> are distributed, but you know E[<em>X</em> ²] and E[<em>Y</em>], then it's as simple as distributing the expectation over the sum:
E[2<em>X </em>² - <em>Y</em>] = 2 E[<em>X </em>²] - E[<em>Y</em>]
Or, if you're given the expectation and variance of <em>X</em>, you have
Var[<em>X</em>] = E[<em>X</em> ²] - E[<em>X</em>]²
→ E[2<em>X </em>² - <em>Y</em>] = 2 (Var[<em>X</em>] + E[<em>X</em>]²) - E[<em>Y</em>]
Otherwise, you may be given the density function, or joint density, in which case you can determine the expectations by computing an integral or sum.
Hi <span>Camrynb10705oxknsv!
So let's take a look at the answers they give. A is 2.5 - 2.2 and all that is is switching the numbers so that isn't right. B they do addition instead of subtraction so that can't be right. C they do 2.2 + (-2.5) and when you add a negative number it's like subtraction because a negative number is under 0 and so your adding a number under 0 so you go down. So the answer is C.
If you need me to explain it different let me know. Hope this helps!</span>
Answer: The answer is around 16.66%
