Chapter 1 Lesson 1.4 The Role of Statistics and the Data Analysis Process

1.4: Types of Data and Some Simple Graphical Displays Vocabulary Univariate Data Set: A data set consisting of observations on a single characteristic/variable. Bivariate Data Set: A data set consisting of observations on two characteristics/ variable. Examples?

Vocabulary Variable: Any characteristic whose value may change from one individual/object to another. Categorical e.g. hair color Quantitative (Numerical) e.g. how many hours of fun Example: See Handout

Vocabulary Categorical Quantitative –Discrete variables can take one of a finite number of distinct outcomes (isolated points on a #-line.) Example: –Continuous variables can take any numeric value within a range of values (interval on a #-line.) Example:

Frequency and Relative Frequency Refer to pg.13 (4 th ed.) for definitions Example:

Example: Titanic Survival Count by Class What would the relative frequency be (in %s)?

Bar Charts A bar chart displays the distribution of a categorical variable, showing the counts for each category next to each other for easy comparison. A bar chart stays true to the area principle. Thus, a better display for the ship data is this  as opposed to…

Dotplots A dotplot is a simple display. It just places a dot along an axis for each case in the data. The dotplot to the right shows Kentucky Derby winning times, plotting each race as its own dot. You might see a dotplot displayed horizontally or vertically. Use for small numerical (sometimes categorical) data sets.

HOMEWORK Pg.18: #1.12, 1.13, 1.14, 1.17, 1.20, 1.21, 1.24 Quiz