Unit E: Statistics and Probability

Chapter 2: Probability

Practice

Instructions: Click the Download File button to download a printable PDF of the questions. Answer each of the following practice questions on a separate piece of paper. Step by step solutions are provided under the Solutions tab. You will learn the material more thoroughly if you complete the questions before checking the answers.

Practice
Solutions

There are 6 blue morpho butterflies and 9 lacewing butterflies in a display case at the zoo. One of the 15 butterflies escaped.

Blue Morpho Butterfly

Lacewing Butterfly
1. What is the probability that a blue morpho butterfly escaped?
2. What is the probability that a lacewing butterfly escaped?
3. What is the probability that a monarch butterfly escaped?
4. Which type of butterfly is more likely to escape?
Four LEGO^® blocks are in a pile. One LEGO^® block is chosen randomly.
1. What is the probability of choosing a red LEGO^® block?
2. What is the probability of choosing a blue LEGO^® block?
3. What is the probability of choosing a yellow LEGO^® block?
4. Which outcome is the most likely: choosing a red LEGO^® block, choosing a blue LEGO^® block, or choosing a yellow LEGO^® block?

There are 6 blue morpho butterflies and 9 lacewing butterflies in a display case at the zoo. One of the 15 butterflies escaped.

Blue Morpho Butterfly

Lacewing Butterfly

What is the probability that a blue morpho butterfly escaped?
What is the probability that a lacewing butterfly escaped?
What is the probability that a monarch butterfly escaped?
Which type of butterfly is more likely to escape?

$\begin{array}{rcl} probability & = & \frac{number of blue morpho butterflies}{total number of butterflies} \\ = & \frac{6}{15} \\ = & \frac{2}{5} \\ = & 0.4 \end{array}$

Note: The first line of the formula is omitted in the solution in the practice questions because it is not required to be included on the assignment.

The probability that a blue morpho butterfly escaped is 0.4.
$\begin{array}{rcl} probability & = & \frac{number of lacewing butterflies}{total number of butterflies} \\ = & \frac{9}{15} \\ = & \frac{3}{5} \\ = & 0.6 \end{array}$

The probability that a lacewing butterfly escaped is 0.6.
$\begin{array}{rcl} probability & = & \frac{number of monarch butterflies}{total number of butterflies} \\ = & \frac{0}{15} \\ = & 0 \end{array}$

The probability that a monarch butterfly escaped is 0 since there are no monarch butterflies in the display case.
A lacewing butterfly is more likely to escape, since the probability is higher.

Four LEGO^® blocks are in a pile. One LEGO^® block is chosen randomly.

What is the probability of choosing a red LEGO^® block?
What is the probability of choosing a blue LEGO^® block?
What is the probability of choosing a yellow LEGO^® block?
Which outcome is the most likely: choosing a red LEGO^® block, choosing a blue LEGO^® block, or choosing a yellow LEGO^® block?

$\begin{array}{rcl} probability & = & \frac{number of red LEGO blocks}{total number of LEGO blocks} \\ = & \frac{1}{4} \\ = & 0.25 \end{array}$

The probability of choosing a red LEGO^® block is 0.25.
$\begin{array}{rcl} probability & = & \frac{number of blue LEGO blocks}{total number of LEGO blocks} \\ = & \frac{2}{4} \\ = & \frac{1}{2} \\ = & 0.5 \end{array}$

The probability of choosing a blue LEGO^® block is 0.5.
$\begin{array}{rcl} probability & = & \frac{number of yellow LEGO blocks}{total number of LEGO blocks} \\ = & \frac{1}{4} \\ = & 0.25 \end{array}$

The probability of choosing a yellow LEGO^® block is 0.25.
The most likely outcome is choosing a blue LEGO^® block, as the probability of choosing a blue LEGO^® block is the highest.