QMS 102 Lecture Notes - Interquartile Range, Quartile, Frequency (Statistics)
4 Jul 2018
School
Department
Course
Professor
Before Midterm
Data
- Quantitative (numbers) or Qualitative (words)
- Nominal- no particular order ex. gender
- Ordinal- can be ordered, with respective categories ex. ratings
- Interval- 0 does not mean anything ex. Temperature
- Ratio- 0 means something ex. How many textbooks did you buy? 0
- Discrete- whole #
- Continuous- decimal #
Left skewed: mean < median
Right skewed: mean > median
Stem and leaf plot
- Between 6-13 stems
- Stems can be repeated twice or 5x
- Must be one leaf with the first and last stem, or else remove
- Leafs are written in ascending order
- No commas between leaves
- Negative stems have opposite leaves
Frequency Distribution Chart
Steps
1. Find CW by doing
2. Find a nice number ex. 1, 2, 2.5, 5, 10, 20, 25, 50, 100, 200, 250, 500….
3. Using nice number, create frequency distribution chart, with 5-10 classes
4. Check both nice numbers to see if both, one, or none work ex. For CW of 22, check if
there are 5-10 classes for the numbers 20 and 25
Relative Frequency Distribution
- Take the frequency in each class and divide it by the total number of data
- Every class’s relative frequency added up should equal 1
Cumulative Frequency Distribution/OGIVE
- Add the relative frequency along as you go down the chart
- Multiplying it by 100 will give you the percentage, with the total hitting 100% by the end
of the frequency chart
- The second number of the classes should be the horizontal axis
- The crf % should be the vertical axis
- OGIVE should always be going up; never will it fluctuate like a line graph
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Ordinal- can be ordered, with respective categories ex. ratings. Must be one leaf with the first and last stem, or else remove. Steps: find cw by doing, find a nice number ex. 1, 2, 2. 5, 5, 10, 20, 25, 50, 100, 200, 250, 500 : using nice number, create frequency distribution chart, with 5-10 classes, check both nice numbers to see if both, one, or none work ex. For cw of 22, check if there are 5-10 classes for the numbers 20 and 25. Take the frequency in each class and divide it by the total number of data. Every class"s relative frequency added up should equal 1. Add the relative frequency along as you go down the chart. Multiplying it by 100 will give you the percentage, with the total hitting 100% by the end of the frequency chart. The second number of the classes should be the horizontal axis. The crf % should be the vertical axis.
