Question

Kenya is conducting a probability experiment with one number cube with numbers 1 through 6 on each face. She rolls the number cube, records the number on the side that is face up, and repeats the process.

If Kenya rolls the number cube 90 times, what is a reasonable prediction for the number of times that a 1 or a 6 will land face up?

Answer 1

The number cube has 6 equally likely outcomes, so the probability of rolling a 1 or a 6 on any given roll is 2/6 = 1/3.

If Kenya rolls the number cube 90 times, we can use the expected value formula to find the expected number of times that a 1 or a 6 will land face up:

Expected number of 1's or 6's = (number of rolls) x (probability of rolling a 1 or a 6)

Expected number of 1's or 6's = 90 x (1/3)

Expected number of 1's or 6's = 30

Therefore, a reasonable prediction for the number of times that a 1 or a 6 will land face up is 30.