Pre Algebra Statistics (Bivariate Data)

University:
Virtual High School
Course:
STEM | Mathematics
Academic year:

2020
Views:

223

Pages:

2
Author:

Ean Mason

Statistics (Bivariate Data) Intro to Scatter Plots ● A scatter plot is a graph that shows the relationship between two sets of data (bivariable data). The data is graphed on a coordinate plane. ● A scatter plot can be used to determine if an association exists between two variables. ○ The general shape of all the points in a scatter plot can describe the association. ○ To determine the type of association, look at the points on a scatter plot to see if they are grouped closely together. ■ If they are grouped together, this represents clustering. ■ If all the points are clustered in a line, the scatter plot shows a linear relationship. ■ If the points are not clustered in a line, then the scatter plot shows a nonlinear relationship. ■ If there is an outlier, one data point that is far away from all the other points, you do not need to consider it when looking for an association. ● Positive association- an x increases, a y increases ● Negative association- As x increases, y decreases ● No association- The points show no pattern Scatter Plots and Line of Best Fit ● Bivariable data are used to explore the relationship between two variables and can be graphed on a scatter plot ○ If there’s a linear association in the scatter plot, then a line can be used to represent the relationship between the two variables. ● A line of best fit is a straight line that comes closest to most of the points on a scatter plot. The data points should be clustered close to the line with almost an equal number of points above and below the line. The line of best fit will not fit all the data points exactly. ○ A nonlinear association cannot be modeled with a straight line. Two Way Tables ● A scatter plot represents two sets of quantitative data, such as distance, time, or height, ○ Quantitative data can be written with numerical measurements. ● Now we will look at another way to analyze data. A two-way table represents frequencies for two sets of categorical or qualitative data, such as gender, sport, color, or subject. The rows indicate one category, and the columns represent another. Two-Way Frequency Tables ● A relative frequency table shows percentages so that the data can be compared. ● Useful when there’s a lot of data. ● Relative frequency can be calculated for the whole table, the row categories, and/or the column categories.