Let \, X\, be a random varible with invertible cdf \, F_ X. Define another random variable \, Y=F_ X(X). Find the cdf F_ Y of \, Y\,.

For t<0:

F_ Y(t)=\quad
unanswered

For t\geq 1:

F_ Y(t)=\quad
unanswered

For \, 0\leq t< 1:

F_ Y(t)=\quad

1 answer

To find the cdf of Y (denoted as FY), we need to evaluate it for different values of t.

For t < 0, Y = FX(X) takes on a value less than 0 with probability 0 (since FX only takes values between 0 and 1). Therefore, FY(t) = 0.

For t >= 1, Y = FX(X) takes on a value greater than or equal to 1 with probability 1 (since FX only takes values between 0 and 1 and maps to [0, 1]). Therefore, FY(t) = 1.

For 0 <= t < 1, we need to find the probability that Y = FX(X) is less than or equal to t. Since FX(X) is the inverse of FX, this is equivalent to finding the probability that X is less than or equal to FX^(-1)(t). We can express this as:

FY(t) = P(Y <= t) = P(FX(X) <= t) = P(X <= FX^(-1)(t)) = FX(FX^(-1)(t)) = t

Therefore, for 0 <= t < 1, FY(t) = t.