84.5k views
1 vote
Choose a real number uniformly at random in the interval [2, 6], and call it X. Find the CDF of X, F_X(x) Find EX.

User Bandar
by
7.7k points

1 Answer

5 votes

Final answer:

The CDF of a uniformly distributed random variable X on the interval [2, 6] is 0 for x < 2, (x-2)/4 for 2 ≤ x ≤ 6, and 1 for x > 6. The expected value, EX, of this distribution is 4.

Step-by-step explanation:

When we choose a real number uniformly at random in the interval [2, 6] and call it X, we are defining a uniform distribution over the interval. The Cumulative Distribution Function (CDF), F_X(x), for a uniform distribution on the interval [a,b] is given by:

F_X(x) =
0 for x < a,
(x-a)/(b-a) for a ≤ x ≤ b,
1 for x > b.

In this case, a = 2 and b = 6. So for the given interval [2, 6]:

F_X(x) =
0 for x < 2,
(x-2)/4 for 2 ≤ x ≤ 6,
1 for x > 6.

To find the expected value EX of a uniform distribution on [a,b], we use the formula:

EX = (a + b) / 2

Therefore, for our interval [2, 6]:

EX = (2 + 6) / 2 = 4

The expected value of X is therefore 4.

User Ashu Tyagi
by
7.4k points