[ Statistics ] 02. Frequency Distributions and Graphs

1. Organizing Data

Raw data : 수집된 순서대로 처리되거나 순위가 매겨지기 전에 기록된 데이터
→ Original data
Ex_→ 비율척도

Frequency distribution : the organization of raw data in table form, using classes and frequencies.
→frequency table

Categorical Frequency Distributions

→ 명목척도

Grouped Frequency Distributions

Step 1

• Find the highest value and lowest value : 134 & 100
• Find the range : R = H-L = 134 - 100 = 34
• Select the # of classes (usually 5 ~ 20)
  • in this case = 7
• Find the case width
  • $width = \frac{R}{\# of classes}$ = 34 / 7 = 4.9 $\approx$ 5
• Select a starting point : the lowest value = 100

Step 2 : 데이터 집계

Step 3

Cumulative Frequency Distribution

2. Histograms, Frequency Polygons, and Ogives

Histogram

Frequency Polygon

Ogive (cumulative frequency graph)

Distribution Shapes

3. Other Types of Graphs

Bar Graphs

→ only frquency만 의미 O

Pareto Charts

→ order from highest to lowest

Time Series Graph

Pie Graph

Misleading Graph

By changing the units or starting point on the y-axis

By changing the units or starting point on the y-axis

Shown two-dimensionally with circles

By omitting labels or units on the axes of the graph

All graphs should contain a SOURCE for information presented

Stem and Leaf Plots

→ Advantage : not lose information on individual observations

HGU GLS학부 김헌주 교수님의 23-2 통계학 수업을 듣고 작성한 포스트이며, 첨부한 모든 사진은 교수님 수업 PPT의 사진 원본에 필기를 한 수정본입니다.