Unit Title: Samples and populations– Investigation 4 & Commom Core Investigation 3.5 & 3.6
Suggested Time: 8 Days (75- 90 minute Blocks)

Enduring understanding (Big Idea):applying the process of statistical investigation to pose questions, identify ways data are collected, determine strategies for analyzing data and interpreting the analysis In order to answer the question posed; explaining variability in categorical and numerical data; developing a linear equation to characterize a display of data on a scatter plot

Essential Questions: What is a scatter plot? What is the sample? What kinds of comparisons and relationships can I explore using data from the sample? Can I use my results to make predictions or generalizations about the population? What changes about a figure that is dilated? How does the scale factor affect a figure that is dilated? Does the location of the center of dilation affect the size of the dilated figure?

Unit Plans
Common Core Standards Alignment
Connection to 2003 Standards
Investigation 4
Problems 4.1, 4.2, 4.3
Math Reflections
Investigate patterns of association in bivariate data.
8.SP.1 - Construct and interpret scatter plots for bivariate measurementdata to investigate patterns of association between two quantities.Describe patterns such as clustering, outliers, positive or negativeassociation, linear association, and nonlinear association.

8.SP.2 - Know that straight lines are widely used to model relationshipsbetween two quantitative variables. For scatter plots that suggest alinear association, informally fit a straight line, and informally assess the model fit by judging the closeness of the data points to the line.
Goal 4.01, 4.02, 4.03
CC Investigation 3: Transformation (Green Book)
Problems 3.5, 3.6
Understand congruence and similarity using physical models, transparencies, or geometry software.

8.GG.2- Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates.

8.GG.3- Describe the effect of dilations, translations, rotations, and reflections on two-dimensional figures using coordinates.

Prior Knowledge: Collecting and organizing data into different context; for numerical data: finding the range of distribution; using range and shape of distribution of data to make inferences and predictions: for categorical data: analyzing frequencies as counts or percents; collecting and organizing numerical data; understanding units of measure and counts; representing data with line plots, value or frequency bar graphs, stem-and-leaf plots, and coordinate graphs; finding measures of center, examining the behavior of mean and median and shapes of distribution; percents; using counts to report frequencies, tying together work with statistics and probability; comparing data sets using ratios, proportions, rates, or percents; exploring relationships between tables, graphs and equations and investigating linearity.

Mathematical Practices Standards for Common Core
1-Make sense of problems and persevere in solving them 2-Reason abstractly and quantitatively 3-Construct viable arguments and critique the reasoning of others 4-Model with mathematics 5-Use appropriate tools strategically 6-Attend to precision 7-Look for and make use of structure 8-Look for and express regularity in repeated reasoning

Essential Terms Developed in This Unit
Useful Terms Referenced in This Unit
Terms Developed in Previous Unit
Box-and-whisker plot, box plot
Convenience sample
Five number summary
Random sample
Scatter plot
Stem-and-leaf plot, stem plot
Systematic sample
Voluntary-response sample

Measures of center



Categorical data


Line plot

Equally likely

Frequency bar graph




Numerical data




Stem and leaf plot


Samples and Populations

===Data and statistics


Samples and Populations extends the work done throughout sixth and seventh grade with probability and statistics to help students make connections between the two. Students investigate tools for grouping data and comparing distributions, such as line plots, histograms, and box and whisker plots. Students then explore how to collect data (sampling) in a fair method that truly represents the population they are trying to investigate. Finally, students look at relationships between two attributes to see if a pattern can be generated to explain or predict values.

For an in-depth explanation of unit goals, specific questions to ask your student and examples of core concepts from the unit, go to Samples and Populations.

Online resources for Samples and Populations*

Other online resources



Additional Practice/Skills Worksheets

CMP2 Website –online & technology resources

Formal Assessment

  • Check-Ups
  • Partner Quiz
  • Unit Test

Assessment Options

  • Notebook check
  • Multiple-Choice
  • Question Bank
  • ExamView CD-ROM

Parent Guide-Unit Letters

Spanish Assessment Resources


TeacherExpress CD-ROM

LessonLab Online Courses

Unit Technology Tips

Goals of the Unit
The unit Samples and Populations was created to
help students:
• Use the process of statistical investigation to
explore problems
• Use information from samples to draw
conclusions about populations
• Explore the influence of sample size on the
variability of the distribution of sample means
or medians
• Evaluate sampling plans
• Use probability to select random samples from
• Compare sample distributions using measures
of center (mean, median), measures of
variability (range, minimum and maximum data
values, percentiles), and data displays that group
data (histograms, box-and-whisker plots)
• Explore relationships between paired values of
numerical variables

Samples and Populations