Reading and Interpreting Graphs

Bar chart: Compares categories. Read heights of bars. Line graph: Shows trends over time. Focus on slopes (increasing/decreasing). Histogram: Shows distribution of continuous data in intervals (bins). Height = frequency. Dot plot: Each dot = one data point. Easy to find mode, median, range. Pie chart (circle graph): Shows proportions of a whole. Each slice is a percentage of 360°.

Example: A histogram shows test scores: 60-70 (5 students), 70-80 (12 students), 80-90 (8 students), 90-100 (3 students). How many students scored below 80?

Always check: 1. Axis labels: What does each axis represent? What are the units? 2. Scale: Does the axis start at 0? Non-zero starts can exaggerate differences. 3. Title: What is the graph about? 4. Intervals: Are histogram bins equal width? Interpolation: Estimating a value between known data points. Extrapolation: Estimating beyond the data range (less reliable).