Stat 185 - Quiz 1 Practice Problems

We will have a quiz on Wednesday, February 10. It will have four problems very similar to the ones below.

The quiz will be taken via my open math and its format will be a lot like the homework format but there will be a time limit of 45 minutes. There is already a practice version on MyOpenMath that you should definitely try by Tuesday night.

1. I've rigged my Zoom application to keep track of students logging in late. For each late entry, I know by exactly how many minutes the student was late. That data is represented in the histogram above where each bin includes the right endpoint, but not the left endpoint of the the associated interval.
   • How many students where more than two minutes late?
2. My daughter's Halloween bag has 3 Snickers bars, 2 Three Musketeer's bars, and 4 Reece's cup. Suppose I reach in and blindly pull two pieces of candy. What's the probability that I get a Snicker's bar and then a Reece's cup?
3. The table below shows the distribution of a discrete probability distribution $X$. Find the mean, variance, and standard deviation of $X$.

   $X$	1	2	4	6
   $P(X)$	0.4	0.3	0.2	0.1

4. Suppose that $U$ is uniformly randomly distributed over the interval $[2,14]$ (i.e. $U \sim U(2,14)$). Find $P(U < 8)$.