For each one of the following statements, indicate whether it is true or false. (a) If X = Y (i. e., the two random variables always take the same values), then Van X | Y = 0.
(b) If X = Y (the two random variables always take the same values), then Var (X | Y) = Var (X).
(c) If Y takes on the value y, then the random variable Var (X | Y) takes the value E[(X – E[X | Y = y])2 |Y = y].
(d) If Y takes on the value y, then the random variable Var (X | Y) takes the value E[(X - E[X | Y])2 | Y = y].
(e) If Y takes on the value y, then the random variable Var ( X | Y) takes the value E[(X – E[X])2 | Y = y].

Solution :

a).

  Now, if X = Y, then :

Then, E[X|Y] = x = y

So,

                      = 0

Therefore, this statement is TRUE.

b). If X = Y , then Var (X) = Var (Y)

And as Var (X|Y) = 0, so Var (X|Y) ≠ Var (X), except when all the elements of Y are same.

So this statement is FALSE.

c). As defined earlier,

  So, this statement is also TRUE.

d). The statement is TRUE because .

e). FALSE

   Because,

option a is correct.

step-by-step explanation:

scale factor: it is used to find proportional measurements.

proportions means having the same ratio.

scale factor is the ratio of the model measurement to the actual measurement in a simplest form.

or we can say that the ratio of any two corresponding lengths in two similar geometric figures

if the scale factor is more than 1, then it is an enlargement,

if the scale factor less than 1, then it is a reduction.

given the two geometric figure:

by definition of proportions, we have