AKA | Frequency Table |
Classification | Analyzing/Trending (AT) |
A frequency distribution can display in table format quantitative (class intervals) as well as qualitative (categories) data organized in a meaningful order. The FD is often used to group data for histogram, pie chart, or other tools.
To determine how data is distributed over an acceptable range of upper and lower limits.
To sort and group raw data.
To show distribution ratios (percent).
→ | Select and define problem or opportunity |
→ | Identify and analyze causes or potential change |
Develop and plan possible solutions or change | |
Implement and evaluate solution or change | |
Measure and report solution or change results | |
Recognize and reward team efforts |
1 | Research/statistics |
Creativity/innovation | |
4 | Engineering |
Project management | |
2 | Manufacturing |
6 | Marketing/sales |
7 | Administration/documentation |
3 | Servicing/support |
5 | Customer/quality metrics |
Change management |
before
Checksheet
Observation
Data collection strategy
Surveying
Interview technique
after
Histogram
Line Chart
Pie Chart
Two-directional Bar Chart
Trend Analysis
Preparation for Grouping of Data
Determine the range(s) of the distribution
R = (H-L) +1
For smaller data sets, N = < 100: number of class intervals (C.I.) between 5-10
For larger data sets, N = > 100: number of class intervals (C.I.) between 10-20.
Width of the class interval to be 2, 3, 5, 10, 20 for smaller numbers. (Add zeros for larger data sets.)
Select number of class intervals:
Check if the lowest data point in the data set is divisible an equal number of times as those by the C.I. width. If not, select the next lower data point that is.
Note | 9 is used as the lowest score since 10 was not divisible by the C. I. of 3 without a remainder. |
STEP 6 Insert prepared data into the FD table. See example Customer Complaints per Day (quantitative data). Date the table.
Note | For categorical data, construct a FD table as shown in example for customer response data. |
Customer Complaints per Day
A. Customer Complaints/Day | Period = 30 days | |
---|---|---|
Class Interval | Class f | Class rf(%) |
9-11 | 2 | 6.67 |
12-14 | 4 | 13.33 |
15-17 | 7 | 23.33 |
18-20 | 5 | 16.67 |
21-23 | 4 | 13.33 |
24-26 | 4 | 13.33 |
27-29 | 3 | 10.00 |
30-32 | 1 | 3.33 |
Date xx/xx/xx | 30 | 100.00 |
B. Customer Response Data | Total Respondents = 26 | |
---|---|---|
Category | (N) | % |
Strongly agree | 6 | 23.08 |
Agree | 7 | 26.92 |
Neither | 3 | 11.54 |
Disagree | 5 | 19.23 |
Strongly disagree | 3 | 11.54 |
Missing response | 2 | 7.69 |
Date xx/xx/xx | 26 | 100.00 |