1. First Steps: Organizing Data Looking at a set of raw data is like emptying the box of a jigsaw puzzle on a table… it’s just a meaningless jumble of pieces.

2. Organizing Data Frequency distribution - a table which shows how often each value of a variable occur. Consider the following data: 28 20 21 20 17 19 18 26 20 25 15 12 15 15 13 18 21 22 20 13 15 18 20 23 17 24 17 25 17 24 19 18 16 23 18 16 17 20 15 20

3. Ungrouped Frequency Distribution Score f 28 1 19 2 27 0 18 5 26 1 17 5 25 2 16 2 24 2 15 5 23 2 14 0 22 1 13 2 21 2 12 1 20 7 n = 40

4. Grouped Frequency Distribution Score f 27 - 29 1 24 - 26 5 21 - 23 5 18 - 20 14 15 - 17 12 12 - 14 3 n = 40 (interval width = 3)

5. Organizing Data Exact limits - the limits of a score are considered to extend one-half the distance between the smallest unit of measurement above and below the score. 85 86 87 88 89 86.5 87.5 Exact Limits

6. Grouped vs. Ungrouped - ungrouped distributions work best with small ranges - ungrouped distributions contain exact information for all values, but are more difficult to interpret. - grouped distributions usually provide a better “picture” of data, but lose some detail. - grouped distributions work best with large ranges

7. Other Frequency Distributions Score f % f 27 - 29 1 2.5 24 - 26 5 12.5 5 ÷ 40 =.125 21 - 23 5 12.5 18 - 20 14 35.0 14 ÷ 40 =.35 15 - 17 12 30.0 12 - 14 3 7.5 n = 40 Relative frequency distribution - table that contains the proportion or percent for each value or interval. f/n = prop. f/n x 100 = %

8. Other Frequency Distributions Score f cum f 27 - 29 1 24 - 26 5 21 - 23 5 18 - 20 14 15 - 17 12 12 - 14 3 n = 40 Cumulative frequency distribution - table that shows the accumulated frequencies below the upper exact limit of each interval. 29 3 34 15 39 40

9. Other Frequency Distributions Score f cum f % cum f 27 - 29 1 40 100.0 24 - 26 5 39 97.5 21 - 23 5 34 85.0 34 ÷ 40 =.85 18 - 20 14 29 72.5 15 - 17 12 15 37.5 15 ÷ 40 =.375 12 - 14 3 3 7.5 n = 40 Cumulative percent frequency distribution - table that shows the percent of accumulated frequencies below the upper exact limit of each interval. cum f/n = cum prop. f cum f/n x 100 = cum % f

10. Organizing Data Frequency distributions can also be constructed for qualitative data: Major f Biology 529 Chemistry 221 Physics 106 Geology 58 n = 914

11. Construct a relative frequency distribution of the following: Is a Stolen Kiss a Form of Sexual Harassment? Females Males Score f f 5 62 30 4 18 12 3 5 8 2 2 8 1 0 1 n = 87 n = 59

12. Is a Stolen Kiss a Form of Sexual Harassment? Score % females % males 5 71.3 50.8 4 20.7 20.3 3 5.7 13.6 2 2.3 13.6 1 0.0 1.7 n = 87 n = 59