standard_description: Develop a probability model and use it to find probabilities of events. Compare probabilities from a model to observed frequencies; if the agreement is not good, explain possible sources of the discrepancy.
problem_activity: Problem 1
Find the value of each of the following.
a.
$${{1\over4}}$$
of
$${{12}}$$
b.
$${{3\over4}}$$
of
$${{12}}$$
Problem 2
There are 21 students in the chess club.
$$2\over3$$
of them are girls. How many girls are in the chess club?


aligns: no