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S1 One-variable Statistics
In grades 6–8, students used graphical displays (histograms, dot plots and box plots) as a way to summarize data. These graphical displays are revisited in this unit, but with a focus on interpretation and what they reveal about the data in addition to the mechanics of constructing the graphical displays.
Students were introduced to measures of center (mean and median) and measures of variability (mean absolute deviation and interquartile range) in grades 6–8. Understanding of the mean absolute deviation (MAD) provides a foundation for the standard deviation, which is a more widely used measure of variability introduced in this unit.
In this unit on one-variable statistics, students recall the concept of variability to discuss the diWerence between statistical and non-statistical questions while they collect survey data from their classmates and classify that data as numerical or categorical. They represent and interpret data using graphical representations such as dot plots, histograms, and box plots. They describe distributions using the appropriate terminology such as “symmetric, skewed, uniform, bimodal, and bell-shaped.” They graphically represent data and calculate summary statistics using technology, then interpret the values in context. They recognize a relationship between the shape of a distribution and the mean and median. They compare data sets with diWerent measures of variability and interpret data sets with greater MADs or interquartile ranges as having greater variability. They learn that standard deviation is a measure of variability, and they interpret standard deviation in context. They recognize outliers, investigate their source, make decisions about excluding them from the data set, and understand how the presence of outliers impacts measures of center and measures of variability. They compare measures of center and the standard deviation and the interquartile range for diWerent data sets. In the culminating activity, students pose and answer a statistical question by designing an experiment, collecting data, and analyzing data.
A1 Linear Equations, Inequalities and Systems
Early in the unit, students build on their work from middle school to build the more Uexible understanding of variables, expressions, and equations that they will need in high school. They write expressions and equations with many variables to model quantities in
a situation, then consider scenarios in which all but one of the quantities is known, leading to an equation in one variable, for which a solution is a number that makes the equation true. They interpret the meaning of solutions in terms of the situation being modeled. In the third lesson, in preparation for their work on equations in two variables in the next section, they are reminded that a solution to an equation in two variables is a pair of
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Course Guide Algebra