Lecture 9 Quantitative Analysis Codebooks Codebook document used

Lecture 9 Quantitative Analysis

Codebooks • Codebook – document used in data processing and analysis that tells the location and meaning of different items in a data file • Data contained in a codebook – Location of variables – Variable names – Questions/items (variables) – Attributes of variables and code assigned to attributes – May contain frequencies

Example of Codebook Entry

Frequency Distribution • Creating a frequency distribution Value Label Frequency Percent 1 Coke 34 24. 5 2 Dr. Pepper 18 12. 9 3 Fanta 13 9. 4 4 Diet Sprite 5 3. 6 5 Bud Light 18 12. 9 6 Red Bull 5 3. 6 7 Iced Tea 38 27. 3 8 Olympia 8 5. 8 139 100* Total Cumulative Percent * May not add to 100 because of rounding How to calculate percent f/n=% f=frequency n=total 34/139=. 245 Or 24. 5%

Frequency Distribution • Creating a frequency distribution Value Label Frequency Percent Cumulative Percent 1 Coke 34 24. 5 2 Dr. Pepper 18 12. 9 37. 4 3 Fanta 13 9. 4 46. 8 4 Diet Sprite 5 3. 6 50. 4 5 Bud Light 18 12. 9 63. 3 6 Red Bull 5 3. 6 66. 9 7 Iced Tea 38 27. 3 94. 2 8 Olympia 8 5. 8 100 139 100* Total * May not add to 100 because of rounding How to calculate cumulative percent Add percent values by cell. For example: 24. 5+12. 9=37. 4

What is the mode? Value Label Frequency Percent Cumulative Percent 1 Coke 34 24. 5 2 Dr. Pepper 18 12. 9 37. 4 3 Fanta 13 9. 4 46. 8 4 Diet Sprite 5 3. 6 50. 4 5 Bud Light 18 12. 9 63. 3 6 Red Bull 5 3. 6 66. 9 7 Iced Tea 38 27. 3 94. 2 8 Olympia 8 5. 8 100 139 100* Total The mode is Iced Tea because more respondents (27. 3%) selected that option than any other option

What is the median? Value Label Frequency Percent Cumulative Percent 1 Coke 34 24. 5 2 Dr. Pepper 18 12. 9 37. 4 3 Fanta 13 9. 4 46. 8 4 Diet Sprite 5 3. 6 50. 4 5 Bud Light 18 12. 9 63. 3 6 Red Bull 5 3. 6 66. 9 7 Iced Tea 38 27. 3 94. 2 8 Olympia 8 5. 8 100 139 100* Total The median is Diet Sprite. The cumulative percent interval for Diet Sprite ranges from 46. 9 to 50. 4.

How to calculate the mean Value Label Frequency Percent Cumulative Percent 1 Coke 34 24. 5 2 Dr. Pepper 18 12. 9 37. 4 3 Fanta 13 9. 4 46. 8 4 Diet Sprite 5 3. 6 50. 4 5 Bud Light 18 12. 9 63. 3 6 Red Bull 5 3. 6 66. 9 7 Iced Tea 38 27. 3 94. 2 8 Olympia 8 5. 8 100 139 100* Total 1. Multiply each value by its frequency. For example: 1 *34 2. Sum all the products from step 1 3. Divide the total from step 2 by the total number of observations (n). In this case 139.

Choosing the Best Measure of Central Tendency • Level of measurement • Choosing the best measure of central tendency – Level of measurement Nominal Ordinal Interval/Ratio Mode Best OK OK Median No Best OK Mean No No Best