The Probability Scale

Question 1

A student says that the chance his school bus will arrive on time tomorrow is about the same as the chance of rolling an even number on a standard six‑sided die. Which number on a 0‑to‑1 probability scale should he write for the bus arriving on time?

Accepted Answer

0.50

Answer

0.33

Answer

0.66

Answer

0.75

Question 2

Why does a fair six‑sided die give each number a probability of 1/6?

Accepted Answer

Because the die has six faces that are all equally likely to land face up, so each face has 1 chance out of 6.

Answer

Because the numbers 1 through 6 add up to 21, and 21 divided by 6 equals 3.5.

Answer

Because you have to roll the die exactly six times to see each number.

Answer

Because the die is made of plastic, which makes each number appear the same number of times.

Question 3

Which of the following everyday events has a probability closest to 0.5 (half) on the 0‑to‑1 probability scale?

Accepted Answer

A tossed fair coin lands heads.

Answer

The school bus arrives on time.

Answer

It rains tomorrow in a desert.

Answer

You receive a birthday present this year.

Try three questions

A student says that the chance his school bus will arrive on time tomorrow is about the same as the chance of rolling an even number on a standard six‑sided die. Which number on a 0‑to‑1 probability scale should he write for the bus arriving on time?

Why does a fair six‑sided die give each number a probability of 1/6?

Which of the following everyday events has a probability closest to 0.5 (half) on the 0‑to‑1 probability scale?

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