Lesson Two-Way Tables Obj: I can 1) Construct two-way tables 2) Use two-way tables to summarize data HWK: Worksheet

Vocab: two-way table- displays two-variable data by organizing it into rows and columns categorical data- when numbers are collected in groups or categories two-way frequency table- a visual representation of the possible relationships between two sets of categorical data relative frequency- how often something happens divided by all outcomes – can be a fraction, decimal or percent joint frequency- entries in the body of the table marginal frequency- the cells that contain the sum of the initial counts by row and by column conditional relative frequency- when a relative frequency is determined based upon a row or column – divide a joint frequency by a marginal frequency total Cumulative frequencies – the totals

Example Basketball Volleyball Total Boys 20 15 35 Girls 10 40 50 30 55 100% Pink boxes are joint frequency Blue boxes are marginal frequency

Ex 1) Marisa took a survey of 100 pet owners to find out whether cats and dogs preferred being inside or outside during the day. Construct a two-way table for the results: 35 out of 50 cats prefer being inside 20 out of 50 dogs prefer being inside

Ex 2) Using the two-way table from Ex 1, include the relative frequencies. Ex 3) Use the two way table to describe relationships that you can see.

Ex 4) Use the following table to answer the questions. Sport Utility Vehicle (SUV) Sports Car Total Male 21 240 = 9% 39 240 = 16% 60 240 = 25% Female 135 240 - 56% 45 240 = 19% 180 240 = 75% 156 240 = 65% 84 240 = 35% 240 240 = 100% How many people responded to the survey? How many males responded to the survey? How many people chose an SUV? How many females chose a sports car? How many males chose an SUV? What percent of the survey takers was female? Was there a higher percentage of males or females choosing an SUV?