Answer:

And using the table from the info we got:

And replacing we got:

Explanation:
For this case we assume that following table shows the distribution of family size in a certain U.S. city
Family Size Probability
2 0.464
3 0.212
4 0.197
5 0.078
6 0.030
7+ 0.019
We assume that X represent the random variable "family size"
And for this case we want to find this probability:

And using the table from the info we got:

And replacing we got:
