Question

The probability for a family having x dogs is given by:

Number of Dogs, x	Probability of x, P(X=x)
0	.3
1	.4
2	.2
3	.1

Find the expected number of dogs that a family will have. Round to the nearest tenth.

Answer 1

Here we have given that x is indicating the number of dogs and probability of x is given respectively in the above table.

Then we have to find out that expected number of dogs that a family will have.

Now, let we define that E[X] indicates the expected no of dogs that a family will have. Thus-

                   = 0 x 0.3 + 1 x 0.4 + 2 x 0.2 + 3 x 0.1

                   = 0   +   0.4 +   0.4 + 0.3

                   = 1.1

After rounding to the nearest tenth, we will get that expected number of dogs that family will have, is - 1.

Hence expected number of dogs is 1.