8D | Data Displays Study Guide

Unit 2: Statistics • Lessons 2.6–2.7 • Standard: 6.DS.5

Key Vocabulary

Histogram — a bar graph that shows data in equal intervals (ranges). Bars touch each other. (histograma)
Dot Plot — a number line with dots above each value to show frequency. (diagrama de puntos)
Box Plot — a diagram that shows the five-number summary (min, Q1, median, Q3, max). (diagrama de caja)
Frequency — how many times a value appears in the data. (frecuencia)
Interval — a range of values grouped together (e.g., 0–9, 10–19). (intervalo)

Types of Data Displays

Dot Plot
• Best for: small data sets, showing each individual value
• How to read: each dot = one data point; stack dots above the number line
  Test Scores:
          *
      *   *   *
  *   *   *   *   *
  |---|---|---|---|---|
  70  75  80  85  90
Histogram
• Best for: large data sets, showing data in ranges (intervals)
• How to read: the HEIGHT of each bar shows the frequency; bars touch each other
• No gaps between bars (unlike a regular bar graph)
Box Plot (Box-and-Whisker)
• Best for: comparing data sets, showing spread and center
• Shows 5 values: minimum, Q1 (lower quartile), median, Q3 (upper quartile), maximum
  |----[=====|=====]--------|
 min   Q1  med   Q3        max

Step-by-Step: Reading Data Displays

  1. 1 Read the title — What is the data about?
  2. 2 Read the labels — What do the axes or number lines represent?
  3. 3 Look at the scale — What are the intervals or values?
  4. 4 Interpret the data — Which interval/value has the most? The least? Are there gaps or clusters?

Watch Out!

Practice Problems

1. Which data display uses dots stacked above a number line?
Type: "dot plot", "histogram", or "box plot".

2. Which data display groups data into intervals with bars that touch?
Type: "dot plot", "histogram", or "box plot".

3. Which data display shows minimum, Q1, median, Q3, and maximum?
Type: "dot plot", "histogram", or "box plot".

4. In a histogram, the height of a bar tells you the _____ (how many data values are in that interval). What word fills the blank?