Displaying Data with Graphs Dot Plot Stemplot Describing

Displaying Data with Graphs Dot Plot Stemplot

Describing a Graph l Center l Shape l Spread

Center If you had to pick a single number to describe all the data – the center would be the best. It’s in the middle! Median – Half the numbers are larger & half are smaller. Mean – average of the numbers

Shape l Are there any peaks? l l Mode – occurs the most often. Is it skewed? Where is the tail? l l Skewed right – the tail is to the right Skewed left – the tail is to the left

Shape – Are there modes? Unimodal Bimodal How many bumps are in the graph? – Those are modes.

Uniform – Don’t appear to have any mode. All bars are approximately the same height.

Symmetric? Can you fold it along a vertical line through the middle and have the edges math pretty closely? If so, then it’s symmetric.

Shape –Skewed? It’s skewed to the side of the longer tail. Negatively Skewed or (Skewed left) Positively Skewed or (Skewed right)

Shape – Unusual Features l Are there any stragglers, or outliers? l Are there any gaps?

Spread – (Variation) • How spread out is the data? • • How spread out is the interquartile range? • • Range – Difference between highest & lowest IQR – the middle 50% Is it tightly clustered around the center or spread out?

We looked at the base salaries of the CEOs of the 800 largest corporations in 1994. l Center – Centered around $500, 000 l Shape – Unimodal, Nearly Symmetric, Some high outliers l Spread – Majority are between $100, 000 and 1, 000. But there a few with salaries between $2, 500, 000 and $3, 000

Dotplots How many classes are you taking?

Homework l Page 42 (37, 39, 41)