Recent content by Jessica21

  1. J

    Calculating Variance for Randomly Drawn Beads in a Necklace

    Um I am not sure if I get what you are trying to say but I have given it some thought and come up with the following! if X1 =1then that means bead 1 = pink and bead 2 = blue , or bead 1 = blue and bead 2 = pink so P (X1 =1 ) = (2/3)(1/3)+ (1/3)(2/3) = 4/9 and P (x1= 0) = 5/9 Do I just...
  2. J

    Calculating Variance for Randomly Drawn Beads in a Necklace

    1. A necklace consists of 5 beads on a string. The beads for making the necklace are drawn at random from a box containing a very large number of beads. 2/3 of the beads are pink and 1/3 are blue. find the mean and variance of the number of unlike pairs of adjacent beads in the necklace. I am...
  3. J

    Finding the expected value of a probability function

    1. Suppose X is a random variable with probability function f(x) = 0.49x(0.3)^ (x-1). Find E(x). 2. E(X) = sum of all x of x*f(x) 3. so I know that E(X) = sum of all x of x*f(x) so E(x)= 0.49* sum of all x of x^2(0.3)^(x-1) But I'm not sure how do i evaluate the sum? Can...
  4. J

    Partial Derivatives: Calculating fₓ and fᵧ (3,1)

    Hi everyone! I was wondering if someone could help me with the following question with partial derivatives. A function f: R^2 -> R is defined by f(x,y) = g(x-2y), where g: R-> R. If g'(1)= 3, calculate f subscript x (3,1) and f subscript y of (3,1). thanks!
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