Will give a brainlist Helppp please

find the expectation e(x) and variance var(x) for the task
suppose you choose a real number x from the interval [2, 10] with a density function of the form f(x) = c/x , where c is a constant

Step-by-step explanation:

on

To find c, we can use ∫∞−∞fX(u)du=1:

1=∫∞−∞fX(u)du

=∫1−1cu2du

=23c.

Thus, we must have c=32.

To find EX, we can write

EX=∫1−1ufX(u)du

=32∫1−1u3du

=0.

In fact, we could have guessed EX=0 because the PDF is symmetric around x=0. To find Var(X), we have

Var(X)=EX2−(EX)2=EX2

=∫1−1u2fX(u)du

=32∫1−1u4du

=35.

To find P(X≥12), we can write

P(X≥12)=32∫112x2dx=716.

d (5 x (-20)) * (100 x (0.7))

step-by-step explanation:

5÷1/100 * -.7 *-20

copy dot flip

5*100 * -.7 *-20

rearrange

5*-20   * 100 *-.7

-100   *-70

7000