It is discrete because the sum of the prob is 1 and each prob is between 0 and 1 inclusive. The mean is 1.518 activities as the number of experiments increases, the mean of the observations will approach the mean of the random variable. The standard deviation is__________________? What is the probability that a randomly selected student has a parent involved in three​ activities?   The probability is ______________.   What is the probability that a randomly selected student has a parent involved in three or four​ activities?

Chapter 6 question 10.  

Hello, Can you help me solve the last portions of this last problem in this chapter?

In the following probability distribution, the random variable x represents the number of activities a parent of a 6th to 8th grade student is involved in, complete a through f below.

x =        0                 1                2              3                   4

P(x)=    0.228           0.381         0.101       0.225            0.065

It is discrete because the sum of the prob is 1 and each prob is between 0 and 1 inclusive.

The mean is 1.518 activities

as the number of experiments increases, the mean of the observations will approach the mean of the random variable.

The standard deviation is__________________?