6.DS.4 Lesson 2-8-part2 Apply Day · Set B
MASTERY CHECK
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2.8 · Part II

Second Practice Form · Independent Application and Spiral Review

Mean · Average

Interactive Workbench & Models →
Name: Date: Period: Learning Goal:
■ ADVANCED CONCEPT ANCHOR: 2.8 · Part II
1Measures of Center: Mean
2The Structural Procedure
  1. Add all data values together to find the total sum
  2. Divide the sum by the count of data values
  3. Concept: The mean represents the fair share or balance point of the data
3Mathematical Word Bank
  • Mean (Media) — The average of a data set. Add all the values, then divide by how many values there are.
  • Average (Promedio) — Another word for the mean — the amount each value would be if the total were shared equally.
  • Measure of center (Medida de centro) — A single number used to describe the middle, or typical value, of a whole data set.
  • Balance point (Punto de equilibrio) — The value where the total distance of the data above it equals the total distance below it. The mean is the balance point.
  • Data set (Conjunto de datos) — The whole collection of values that were gathered or measured.
4Watch out
  • The most common mistake with the mean is adding correctly and then dividing by the wrong number — or not dividing at all. Students report the total (for 8, 10, 6, 12 they say the mean is 36) or they divide by a count that does not match the data, such as dividing a 4-value total by 5, or skipping a zero when counting the values. Before you finish, do two things: count the values in the data set out loud, and check that your mean lands between the smallest and largest value. A mean of 36 for data that never goes above 12 is impossible.
SECTION 1 REAL-WORLD CONTEXTS & PROBLEM SOLVING [Applications]
  1. 1 MULTIPLE CHOICE

    Miguel earned $60 walking dogs over 4 days. Ana says his mean daily earning is $15. Beto says you cannot know, because Miguel might have earned nothing on some days. Who is right?

    1. AAna — the mean spreads the total evenly and does not claim he earned $15 each day
    2. BBeto — a mean is meaningless when the daily amounts are unknown
    3. CBoth — the mean is $15 but it is not a useful number
    4. DNeither — the mean is $240
    ✏️ Workspace & Solution Steps
  2. 2 MULTIPLE CHOICE

    Find the mean of: 4, 6, 8, 10

    1. A7
    2. B28
    3. C8
    4. D6
    Put the data in order
    Work
  3. 3 MULTIPLE CHOICE

    Miguel earned $60 walking dogs over 4 days. What is his mean daily earning?

    1. A$15
    2. B$60
    3. C$4
    4. D$20
    ✏️ Workspace & Solution Steps
  4. 4 MULTIPLE CHOICE

    Find the mean of: 3, 5, 7, 9, 11

    1. A7
    2. B35
    3. C9
    4. D5
    Put the data in order
    Work
SECTION 2 MATHEMATICAL WRITING & ERROR ANALYSIS [Reasoning & Critique]
  1. 5 OPEN RESPONSE

    Sofia realized she made an error: she actually scored 12 points in Game 8, not 10. Her other games are unchanged (12, 20, 16, 11, 17, 14, 15, and 18). How does this change the number of points she needs in Game 10 to average 15 points per game? Show how you know.

    ✏️ Mathematical Justification & Response
📐 CER MATHEMATICAL PROOF MATRIX (CER 2.0) SMP.3 / Proof & Justification

Writing Task: Justify why your mathematical solution is accurate and complete.

C Claim
State your direct mathematical answer/claim with units.
E Evidence
Cite exact numbers, calculations, dimensions, or graph data.
R Reasoning
Explain the mathematical theorem, property, or definition connecting evidence to claim.
Student Mastery Self-Assessment:
1 · Need More Support
2 · Getting Closer
3 · Got It / Solid
4 · Master / Can Teach It