AP STATISTIC LESSON 1-1 EXPLORING DATA DISPLAYING DISTRIBUTION WITH GRAPHS

ESSENTIAL QUESTION: What is the Study of Statistics and how can data be displayed to be interpreted? To define the terms of Statistics. To use bar graphs, pie charts, dotplots, stemplots, and histogram graphs to display data. To describe data center, shape and spread. To use ogive, and time plots to find seasonal, and trends in data.

Warm – up Activity 1 (page 4) How Fast Is Your Heart Beating?

Statistical Thinking How to tell the facts from the artifacts.  Statistics uses data to gain insight and to draw conclusions. Data illuminates.  What percent of the American population do you think is white? Look on page XII. Data beats anecdotes and beware of lurking variables.  How data is collected is an art. Anecdotes that are compelling stories and the way that data is compiled and analyzed helps to reveal the facts from the perceived.

Statistical Thinking (continued) Where the data comes from and how it was collected is important.  Collecting data is an art when the truth is sought. Variation is everywhere and conclusions are not certain.  A number does not represent an exact truth, but a range of possibilities.

Introduction Individuals: The objects described by data. Variable: Any characteristic of an individual. Categorical data: Places an individual into several groups or categories. Quantitative variable: Variables that take numerical values. These variables can have operations such addition and averaging. Distribution: Variable tells us what values the variable takes and how often it takes these values. Exploratory data analysis: Using statistical tools and ideas to describe data’s main features.

Questions to ask about data Who? What individuals does the data describe? What? How many variables are there? What are the exact definitions of these variables? Why? What is the reason the data were gathered?

When examining data … Begin by examining each variable by itself. Go to comparing variables. Use graph or graphs. Finally, use numerical summaries.

Displaying distributions with graphs To display categorical variables with a bar of circle graphs. Bar graphs: Step 1: Label your axes and title your graph. Step 2: Scale your vertical axis’ Step 3: Draw a vertical bar above each category name to a height that corresponds to the count in that category.

Circle graphs: Step 1: Find the percent of the data. Step 2: Find the angle that divides the circle into that percent. Step 3: Divide the circle into the parts represented by each categorical variable and label each part with it’s proportion. To create a circle graph you must know the total of all the parts of the data.