Standard Construct and interpret scatter plots for bivariate measurement data to investigate patterns of association between two quantities. Describe patterns such as clustering, outliers, positive or negative association, linear association, and nonlinear association.

Texting and Grades I

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Alignments to Content Standards: 8.SP.A.1

Student View

Task

Medhavi suspects that there is a relationship between the number of text messages high school students send and their academic achievement. To explore this, she asks each student in a random sample of 52 students from her school how many text messages he or she sent yesterday and what his or her grade point average (GPA) was during the most recent marking period. The data are summarized in the scatter plot of number of text messages sent versus GPA shown below.

Task_1_d5daea7b1d897320658891d30db48176

Describe the relationship between number of text messages sent and GPA. Discuss both the overall pattern and any deviations from the pattern.

IM Commentary

The student should address the form of the relationship (linear, curved, etc.), direction (positive or negative), and strength of the relationship between the two variables, and also point out any unusual observations.

Solution

The scatter plot shows a moderate negative linear relationship between the number of texts a student sends and his or her GPA. There is one outlier that has a particularly low GPA and high number of texts sent, though it is in keeping with the overall pattern. It appears that students who send more text messages tend to have lower GPAs.