NDSA Grade 8 Statistics and Probability. Practice it free.

Analyzes bivariate data and investigates associations between data sets. This Grade 8 reporting domain maps to 2 practice skills and 8 representative questions from the playable bank.

Grade 88.SP2 mapped skills
What the test measures

Statistics and Probability skills

  1. Investigate patterns of association in bivariate data.

  2. Construct and interpret scatter plots and use them to make predictions.

Standards basis

North Dakota State Content Standards for Mathematics — North Dakota

How the NDSA reports it

North Dakota administered its own state assessment program (the NDSA, a Cambium computer-adaptive test in grades 3-8 and 10; replaced by ND A+ beginning spring 2025). An official NDSA mathematics public-facing CAT blueprint (Cambium/NDDPI, Oct 2020) does exist and lists per-grade reporting categories with percentage ranges, but its full per-grade table could not be retrieved character-for-character from a citable primary source for transcription here (the Cambium content CDN blocks programmatic access). The NDSA reporting categories are the CCSS-M grade-level domains: the assessment was built on North Dakota's 2017 math standards, which are verbatim CCSS-M organized by grade-level domains. The coverage map below uses North Dakota's 2023-standards-style domain/standard codes (e.g. 3.AR.OA) but the skill content is CCSS-M.

Blueprint & weighting

An official NDSA mathematics CAT blueprint (Cambium/NDDPI public-facing CAT version, Oct 2020) publishes per-grade reporting-category percentage ranges (e.g. grade 3 Operations and Algebraic Thinking ~31-34%, Number and Operations in Base Ten ~22-24%; grade 6 groups Ratios & Proportional Relationships and The Number System ~28-34% and Expressions and Equations ~25-29%). The complete per-grade table could not be retrieved verbatim from a citable primary source (the Cambium content CDN returns HTTP 403 to programmatic fetches), so domain weights in the mapping are left null rather than transcribing partial/uncertain figures or splitting blueprint percentages across the grade-6+ domain groupings.

Try it now

8 free questions · 0/0 correct

Practice playeasy

A trend line for miles jogged xx and calories burned yy is y=90x+20y = 90x + 20. How many calories does the line predict for a 44-mile jog?

y=90(4)+20=360+20=380y = 90(4) + 20 = 360 + 20 = 380 calories.

Practice playeasy

A two-way table has rows Chess/Art and columns 7th/8th: Chess&7th=9, Art&7th=4, Art&8th=11. The Chess row total is 15. How many students are Chess&8th?

Chess row total minus the known Chess cell: 159=615-9=6.

Practice playeasy

A trend line predicts Mia will spell 1818 words correctly in a spelling bee. She actually spells 2121 words correctly. What is the residual (actual minus predicted)?

Residual =2118=3= 21 - 18 = 3 words.

Practice playeasy

A two-way table has rows Bike/Scooter and columns Morning/Afternoon: Bike&Morning=11, Bike&Afternoon=7, Scooter&Morning=5. In all, 29 trips were recorded. How many trips are Scooter&Afternoon?

The three known cells sum to 11+7+5=2311+7+5=23, so the missing cell is 2923=629-23=6.

Practice playeasy

A line of best fit for the number of lawns Jaden mows xx and his savings yy in dollars is y=15x+40y = 15x + 40. According to the line, how many dollars did Jaden have saved before mowing any lawns?

At x=0x = 0 lawns, y=40y = 40: the yy-intercept is the starting savings.

Practice playeasy

A two-way table has rows Dog/Cat and columns Boys/Girls: Dog&Boys=10, Dog&Girls=6, Cat&Boys=5, Cat&Girls=9. How many were surveyed in total?

Add all cells: 10+6+5+9=3010+6+5+9=30.

Practice playeasy

A trend line for hours studied xx and quiz score yy is y=4x+62y = 4x + 62. What score does the line predict for a student who studies 33 hours?

Substitute x=3x = 3: y=4(3)+62=12+62=74y = 4(3) + 62 = 12 + 62 = 74.

Practice playeasy

A two-way table has rows Dog/Cat and columns Boys/Girls: Dog&Boys=10, Dog&Girls=6, Cat&Boys=5, Cat&Girls=9. How many chose Dog in total?

Row total for Dog: 10+6=1610+6=16.

Keep practicing

Turn statistics and probability into game time.

The NDSA placement starts with this test's real coverage map and finds the right difficulty.