Question

find the expected value and variance of the number of heads appearing when two fair coins are tossed.

Answer 1

Answer:

Propability of getting head and tail is one in coin so the probability of getting head is one upon two and getting tail is one upon two

Answer 2

Answer:

1/2

Step-by-step explanation:

Possible combinations when 2 coins are tossed :-

A = { HH, HT, TH, TT}

X = Number of heads

X  -   0                   1                  2

X² -   0                  1                  4

P(X)-  1/4               1/2              1/4

x(bar) - ∑PiXi = 1/4(0) + 1/2(1) + 1/4(2) = 1

Variance =    ∑PiXi² - x(bar)² = 1/4(0)² + 1/2(1)² + 1/4(2)²  - 1² =  3/2 - 1 = 1/2