Quiz 1
Give an example of a discrete and a continuous random variable.

Random variables have two primary characteristics:  they are random and the have numerical values.  Your answer should have both characteristics.  

Examples of good answers include:
the number of body piercings on a randomly selected member of the class (discrete)
the amount of time a randomly selected member of the class slept last night (continuous)
the number of people who show up to class on a given day (discrete)
the circumference of a person's biceps sometime after given a nutritional supplement (continuous)
the actual mileage of a randomly selected car (continuous)
hangtime of a football kicked at the start of the game (continuous)

Some answers that almost, but not quite, made it:
"height of people in class" --  there's no indication of a random mechanism.  Or which people.  Is it the total height of everyone in the class?  If so, then this is not a random number.  is the height of a particular person? This is also not random, because a person's height doesn't change?  To fix this, it should say "The height of a randomly selected person in class".  While we might know everyone's height, if we randomly select someone, we don't know their height until they are chosen.

"shoe size of a sample of basketball players" -- samples don't wear shoes.  People do.  So once you've got these basketball players' shoe sizes, what do you do with those numbers?  And is the sample randomly chosen?  If its the Lakers, then you know (or could find out) their shoe sizes, and there's nothing random about this.

"# of clothes" --- of whom?  This is a number, but not random.

"A couple has three children and they want to know the probabilities of each outcome"  This was a common error;  the values mentioned here are probabilities.  Random variables have probabilities associated with them, but they are not probabilities.  To fix this: "the number of boys a couple will have if they have three children" or "the number of boys in a randomly selected family of 3 children"

"Does a person drive a car, truck, or SUV"  -- there's no randomization mechanism, but also there's no numerical value.  This can be fixed by saying "The RV is a 1 if a randomly selected person drives a car, 2 if he/she drives a truck, 3 if an SUV."