I. Vocabulary. Two-way Frequency table: a table listing two categorical variables who values have been paired.

Transcription

1 I. Vocabulary Two-way Frequency table: a table listing two categorical variables who values have been paired. Joint relative frequency: is found by dividing a frequency that is not in the Total row or the Total column by the grand total. Marginal relative frequency: is found by dividing a row total or a column total by the grand total. Two-Way relative frequency table: displays both the joint relative and marginal relative frequencies. Conditional relative frequency: is found by dividing a frequency that is not in the Total row or Total column by the frequency s row total or column total.

2 II. Creating a Relative Frequency Table: Jenna asked 40 randomly selected students whether they preferred dogs, cats or other pets. Complete the table for both decimals and percents Frequency Relative Frequency Decimals = = = = 1.00 Relative Frequency Percents 45% 30% 25% 0%

3 II. Creating a Two-Way Frequency Table: Jenna also recorded the gender of each student. The results are shown in the two-way frequency table. Find the totals and answer the questions Totals ) How many total students took the survey? 40 2) How many total boys took the survey? 24 3) How many students said they like dogs as pets? 4) How many boys said they like dogs as pets? 18

4 III. Creating a Two-Way Relative Frequency Table: Jenna also recorded the gender of each student surveyed, complete the two-way frequency table below Totals Totals 40 = = = = = =.60 = = = = = = 1.00

5 Creating a Two-Way Relative Frequency Table: Totals 40 = = = = State the percents for the table above. = =.60 = = = = = = 1.00 Totals Old Holt 4-5/4-6; New Holt -1/-2/-3 25% 12.5% 22.5% 60% 20% 17.5% 2.5% 40% 45% 30% 25% 0%

6 Creating a Two-Way Relative Frequency Table: 25% 12.5% 22.5% 60% 20% 17.5% 2.5% 40% Totals 45% 30% 25% 0% 1) Find the joint relative frequency of students surveyed who are girls and prefer dogs as pets. 20% 2) Find the joint relative frequency of students surveyed who are boys and prefer cats as pets. 12.5% 3) Find the marginal RF of students surveyed who prefer dogs as pets and then prefer cats as pets. dogs - 45% cats - 30%

7 IV. Calculating a Conditional Relative Frequency: Totals Find the conditional relative frequency that a student surveyed prefers cats as pets, given the student is a girl. Number of girls who prefer cats: Number of girls: 7 16 =.4375 = 43.75%

8 Calculating a Conditional Relative Frequency: Totals Find the conditional relative frequency that a student surveyed is a girl, given that the student prefers cats as pets. Number of girls who prefer cats: 7 Number of students who prefer cats: 12 =.583 = 58.3%

9 Calculating a Conditional Relative Frequency: Totals Find the conditional relative frequency that a student surveyed prefers cats as pets, given the student is a boy. Number of boys who prefer cats: Number of boys: 5 24 =.208 = 20.8%

10 Calculating a Conditional Relative Frequency: Totals Find the conditional relative frequency that a student surveyed is a boy, given that the student prefers dogs as pets. Number of boys who prefer dogs: Number of students who prefer dogs: 18 =.556 = 55.6%

11 Old Holt 4-5/4-6; New Holt -1/-2/-3 Graph the Two-Way Relative Frequency Table: 25% 12.5% 22.5% 60% 20% 17.5% 2.5% 40% Totals 45% 30% 25% 0% What benefit can these graphs provide in analyzing the data? Visual analysis; quicker/faster comparison of the data; scales; colors

12 V. Graph the Two-Way Relative Frequency Table: 25% 12.5% 22.5% 60% 20% 17.5% 2.5% 40% Totals 45% 30% 25% 0% Dog s 0 What benefit can these graphs provide in analyzing the data? Visual analysis, quicker/faster comparison of the data, scales, colors

13 VI. Finding Possible Associations and Trends Jenna survey results (numbers vs percents). Dog Cat Total /25% 5/12.5% 9/22.5% 24/60% 8/20% 7/17.5% 1/2.5% 16/40% Totals 18/45% 12/30% /25% 40/0% 1) Does the table reflect gender bias towards pets? But, it does imply, boys like other pets more than girls: 22.5% to 2.5%, 2) If so, which gender, likes which pets the best? 3) What are some examples of other pets? N/A NO Hamsters, gerbils, mice, rats, snakes, rabbits, pigs, etc., 4) tend not to like which types of pets? other types