Grade 9 Lesson plan
Bickerstaff Lake Swim Advisory: Reading Bacteria Counts
A 50-minute grade 9 lesson where students summarize bacteria sample data from two fictional beaches and decide whether the county should post a swim advisory.
Common Core Math · High School
HSS-ID.A.2 Compare center and spread of two data sets
Use statistics appropriate to the shape of the data distribution to compare center (median, mean) and spread (interquartile range, standard deviation) of two or more different data sets.
Why water teaches this standard well
Students compare the mean and standard deviation of chlorine-residual readings between two treatment plants to judge which one holds a more consistent disinfectant level. Comparing center and spread across two real plants is exactly how a regulator evaluates operational consistency.
Materials tagged with this code are written to the full standard , and each carries a written note explaining the alignment. See how we review materials.
21 materials aligned to HSS-ID.A.2
Lesson plans
Grade 12 Lesson plan
Threlwood Activated Sludge: Settling Data for a Lab Analyst
Students work as wastewater lab analysts, calculating sludge volume index for two aeration basins and comparing the center and spread of a week of readings.
Grade 10 Lesson plan
Vasserly Creek Sampling: Comparing Two Sites by Center and Spread
A 50-minute grade 10 lesson where students compare eight weeks of turbidity readings from two fictional creek sites using mean, median, IQR, and an outlier test.
Grade 11 Lesson plan
Brackenford Water Bills: Is the Rate Affordable?
A 50-minute grade 11 math lesson where students compute water-bill burden as a percent of income, compare it to a common 4.5% threshold, and project a rate increase.
Grade 11 Lesson plan
Harlow Springs and Odell Flats: Comparing Hardness Spread
A grade 11 statistics lesson comparing the center and spread of two fictional source-water hardness data sets and interpreting how an outlier shifts the mean.
Grade 12 Lesson plan
Aldous and Brenmoor Plants: Comparing Residual Consistency
A grade 12 statistics lesson comparing the mean and spread of daily chlorine residuals from two fictional plants, and testing how one outlier shifts each measure.
Grade 12 Lesson plan
Water Main Break Trends and Capital Planning in Milbrook
A grade 12 lesson comparing the mean and standard deviation of main breaks across pipe materials in a fictional utility, connected to national funding trends.
Worksheets
Grade 11 Worksheet
Comparing Home Chlorine Readings on Two Brookfield Streets
A grade 11 statistics worksheet on a fictional town's home chlorine readings: compare two streets by IQR and standard deviation, then test an outlier.
Grade 11 Worksheet
Penncroft Filter Turbidity: A Compliance Report Worksheet
A grade 11 careers worksheet in which a compliance coordinator compares two filters' turbidity readings by median, IQR, and outlier test before filing a monthly report.
Grade 11 Worksheet
Redbank Well Nitrate Chart: Choosing an Axis Origin
Grade 11 students size bars for a fictional utility's nitrate chart, compare a zero baseline with a cut axis, and judge a newsletter claim built on the cut version.
Grade 11 Worksheet
Selby Reach Monitoring Data: Turbidity and Chlorine Statistics
A grade 11 worksheet where students compute the mean, median, and range of a week of turbidity and chlorine readings and compare them to treatment standards.
Grade 11 Worksheet
Windham Creek Dissolved Oxygen: Comparing Seasonal Spread
A grade 11 statistics worksheet comparing summer and winter dissolved-oxygen readings from a fictional creek using mean, median, IQR, standard deviation, and outliers.
Grade 11 Worksheet
Ilminster's Trihalomethanes: Water Age and Running Averages
A grade 11 worksheet on disinfection byproducts: students compute running annual averages at four sites, tie them to water age, and weigh a main-flushing program.
Grade 11 Worksheet
Otterburn Plant Chlorine Residual: Comparing Shift Statistics
A grade 11 statistics worksheet comparing the center and spread of two shifts of chlorine-residual data at a fictional plant, with an outlier from a pump error.
Grade 11 Worksheet
Harmon Ridge vs. Cutler Bend: Comparing Chlorine Residual Consistency
A grade 11 worksheet where students calculate the mean and standard deviation of two fictional treatment plants' chlorine residual data to compare consistency.
Math problem sets
Grade 11 Math problem set
Two Intakes at Marden and Culliton: Turbidity Statistics
A grade 11 statistics set comparing a week of turbidity from two fictional intakes with mean, median, IQR, standard deviation, and an outlier test.
Grade 9 Math problem set
Redbank vs. Talbot Ridge: Comparing Chlorine Residual Consistency
A grade 9 statistics problem set comparing the mean and standard deviation of chlorine residual readings from two fictional treatment plants.
Labs & experiments
Grade 12 Lab / experiment
Quarryhill Soap Titration: Calibrating a Water Hardness Test
A grade 12 chemistry lab where students calibrate a soap titration with Epsom-salt standards, estimate tap-water hardness as CaCO3, and check it against EDTA.
Grade 12 Lab / experiment
Jar Test Coagulation on Brindle Creek Water: Finding the Dose
A grade 12 lab where students run a five-jar coagulation test on fictional muddy source water, rate settled clarity, and find the lowest effective alum dose.
Projects
Grade 11 Project
Vireo Lake Plant: A Chlorine Residual Control-Chart Study
A four-session grade 11 statistics project building a control chart from a fictional plant's 20-day records and writing a compliance memo to a water board.
Quizzes & test questions
Grade 11 Quiz & test questions
Pellow River Nitrate: A Grade 11 Statistics Unit Test
A 30-point grade 11 statistics test on a fictional river's nitrate data, with items on spread, margin of error, and least-squares regression.