options: Know that straight lines are widely used to model relationships between two quantitative variables. For scatter plots that suggest a linear association, informally fit a straight line, and informally assess the model fit by judging the closeness of the data points to the line.

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.

Use the equation of a linear model to solve problems in the context of bivariate measurement data, interpreting the slope and intercept. For example, in a linear model for a biology experiment, interpret a slope of 1.5 cm/hr as meaning that an additional hour of sunlight each day is associated with an additional 1.5 cm in mature plant height.

Understand that patterns of association can also be seen in bivariate categorical data by displaying frequencies and relative frequencies in a two-way table. Construct and interpret a two-way table summarizing data on two categorical variables collected from the same subjects. Use relative frequencies calculated for rows or columns to describe possible association between the two variables. For example, collect data from students in your class on whether or not they have a curfew on school nights and whether or not they have assigned chores at home. Is there evidence that those who have a curfew also tend to have chores?
problem_activity: A random group of 6th and 8th grade students at a school are asked the question: Do you prefer to complete your homework on a computer or on paper?
Of the 56 sixth graders, 18 answered computer and 38 answered paper.
Of the 60 eighth graders, 52 answered computer and 8 answered paper.
a.   Create a two-way table to represent the data. Label your rows as 6th graders and 8th graders.
b.   What is the proportion, of all of the students, who are in 8th grade and prefer to complete their homework on a computer?
c.   Of the students who prefer to complete their homework on paper, what proportion are in 6th grade?
d.   A student is selected at random from either the 6th or 8th grade at this school. What do you predict is this student's  preferred method of completing their homework? Explain your reasoning.


correct_option_index: 3