Question

Let X be a positive discrete random variable. It is known that E[X^2] = 7.8 and SD(X) = 2.3 (i.e. standard deviation of X). What is the value of E[X]? A) 66.13 B) 2.51 C) 13.09 D) 1.5843 E) 10.1

Name: let x be a positive discrete random variable it is known that eix2 78 and sdx 23 ie standard deviation of x what is the value of ex a 6613 b 251 c 1309 d 15843 e 101 24477
Uploaded: 2023-05-05T12:40:12-08:00
Duration: 1 min 16 s
Channel: Pritesh Ranjan
Description: let x be a positive discrete random variable it is known that eix2 78 and sdx 23 ie standard deviation of x what is the value of ex a 6613 b 251 c 1309 d 15843 e 101 24477

          Let X be a positive discrete random variable. It is known that E[X^2] = 7.8 and SD(X) = 2.3 (i.e. standard deviation of X). What is the value of E[X]?
A) 66.13
B) 2.51
C) 13.09
D) 1.5843
E) 10.1

Added by Ramon S.

Elementary Statistics a Step by Step Approach

Allan G. Bluman 9th Edition

Instant Answer

Solved by Expert Pritesh Ranjan

05/05/2023

Step 1

8. This means that: E[X^2] = Σ(x^2 * P(X=x)) where Σ is the sum over all possible values of X. We can use this formula to find the variance of X: Var(X) = E[X^2] - (E[X])^2 Substituting the given values, we get: Var(X) = 7.8 - (E[X])^2 We also know that SD(X) Show more…

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Let X be a positive discrete random variable. It is known that E[X^2] = 7.8 and SD(X) = 2.3 (i.e. standard deviation of X). What is the value of E[X]? A) 66.13 B) 2.51 C) 13.09 D) 1.5843 E) 10.1