# Lesson 1

Two-way Tables

- Let’s look at categorical data.

### Problem 1

This two-way table shows the results of asking students if they prefer to have gym class in the morning or the afternoon.

morning | afternoon | total | |
---|---|---|---|

grade 6 | 15 | 8 | 23 |

grade 8 | 18 | 21 | 39 |

grade 10 | 12 | 26 | 38 |

total | 45 | 55 | 100 |

- How many students participated in the survey?
- How many students in grade 8 prefer to have gym in the morning?
- How many grade 10 students participated in the survey?
- How many students prefer to have gym in the afternoon?

### Problem 2

A random sample of adults are asked about their preferences for a first dinner date with someone. Complete the two-way table so that it has the characteristics listed.

- 122 people responded to the survey.
- 50 of the people who said they order dessert said they also prefer to split the check.
- 68 people prefer splitting the check.
- 56 people prefer to skip dessert rather than ordering one.

order dessert | no dessert | |
---|---|---|

split the check | ||

one person pays |

### Problem 3

Students in the 7th, 8th, and 9th grade were asked whether they prefer to write in pen or pencil.

- 40 students prefer to write in pen.
- 60 students prefer to write in pencil.

Create values that could represent the number of students in the 7th, 8th, and 9th grade that responded to the survey.

### Problem 4

A recent study observed the number of bike riders ages 0 to 20 that wear helmets. The results are represented in the table.

wear helmet | did not wear helmet | |
---|---|---|

0-5 years | 21 | 4 |

6-10 years | 34 | 14 |

11-15 years | 14 | 18 |

16-20 years | 3 | 12 |

Make an observation based on a data value that is not in the table. Explain your reasoning.