What is 23.7 minus 11.82

Option C

Step-by-step explanation:

Let X be a discrete random variable that counts the number of siblings a randomly selected student has. Then the expected value of X is defined as:

Where is the probability that a randomly selected student has siblings

With

So in this case we know that

#of siblings 0        1        2        3        4         5

probability 0.20 0.65 0.08  0.04  0.02  0.01

Therefore:

The answer is the option C.