Which of the following is a discrete random variable? A. The height of water-oak trees B. The amount of mercury found in fish caught in the Gulf of Mexico C. The number of times a student guesses the answers to questions on a certain test D. The amount of gasoline purchased by a customer

C. The number of times a student guesses the answers to questions on a certain test

Step-by-step explanation:

The difference between a discrete random variable and a non-discrete random variable is that the discrete random variable is countable and doesn't include fractions, one the other hand, non-discrete random variable can have infinite number of values between two values.

Examples of discrete random variables:

The number of times a student guesses the answers to questions on a certain test can only have countable values. 5, 10, 12 etc

Example non-discrete random variables:

The height of water oak trees can have values in fractions. 12.2 feet etc.  

The amount of mercury found in fish caught in the Gulf of Mexico can have values in fractions. 0.15 grams or 1.5 grams etc.

The amount of gasoline purchased by a customer can have values in fractions. 1.7 liters, 5.4 liters etc.

b i think

step-by-step explanation:

not really sure

24

step-by-step explanation:

the graph shows 30% of students walk. 80 students were questioned, so the number that said they walk is

30% × 80 = 0.30 × 80 = 24