8th Grade STAAR Math Review | TEKS 8.5(G) & 8.5(D) | Independent Practice
Name:
Date:
Period:
FUNCTION RULE: Each x (input) can only have ONE y (output). If an x-value repeats with different y-values → NOT a function!
🖩 SCATTERPLOT: + → table → enter data → Add regression → Read equation | Positive = both up | Negative = one up, one down | None = no pattern
📌 REFERENCE CHEAT SHEET — Identifying Functions
Part A: Is It a Function? (Problems 1–6)
1 Is this a function?
{(1, 5), (2, 7), (3, 9), (4, 11)}
Function? Circle: YES / NO Why?
2 Is this a function?
{(2, 4), (3, 6), (2, 8), (5, 10)}
Function? Circle: YES / NO Why?
3 Is this table a function?
x
y
1
5
2
5
3
5
4
5
Function? Circle: YES / NO (Hint: Same y is OK! Check the x-values.)
4 Is this table a function?
x
y
3
1
3
2
3
3
3
4
Function? Circle: YES / NO Why?
5 Is this mapping a function? (Draw arrows from each x to its y.)
Input (x)
1
2
3
→ → → →
Output (y)
5
8
11
14
Note: x = 1 → y = 5, x = 2 → y = 8, x = 2 → y = 11, x = 3 → y = 14
Function? Circle: YES / NO Why?
6 Each Dallas Mavericks player has one jersey number. Is (jersey number → player name) a function?
Function? Circle: YES / NO
"This is / is not a function because _____________________________________________"
Part B: Scatterplots & Trend Lines (Problems 7–10)
7 Dallas monthly high temperatures. Enter into Desmos and find the trend.
Month (x)
1 (Jan)
3 (Mar)
5 (May)
7 (Jul)
9 (Sep)
11 (Nov)
Temp °F (y)
47
65
84
96
90
60
+ → table → enter data → Add regression
Desmos equation: y = ___x + ___
Association: Circle: Positive / Negative / None
"The slope means the temperature changes about _______ °F per month."
8 A survey of Dallas 8th graders — shoe size vs. height. Enter into Desmos.
Shoe Size (x)
6
7
8
9
10
11
Height in. (y)
58
60
63
65
67
70
Desmos equation: y = ___x + ___
Association: Circle: Positive / Negative / None
"As shoe size increases, height _________________ (increases/decreases/stays the same)."
9 Hours studied vs. test score for Dallas students. Enter into Desmos.
Hours (x)
1
2
3
4
6
8
Score (y)
55
62
68
74
85
93
Desmos equation: y = ___x + ___
Association: Slope (m) =
Predict: If a student studies for 5 hours, their predicted score =
"The slope means for each extra hour studied, the score goes up about _______ points."
10 ⭐ CHALLENGE: Dallas restaurant ratings vs. average meal price.
Price $ (x)
8
12
15
20
25
35
Rating /5 (y)
3.2
3.5
3.8
4.0
4.3
4.6
Desmos equation: y = ___x + ___
Association: m = b =
Predict: A $30 meal would have a predicted rating of
"The slope means for every extra $1 in price, the rating goes up by about _______ stars."
✅ Self-Check Before You Turn This In:
☐ Did I check if any x-value repeats before deciding if it's a function?
☐ Did I use + → table → Add regression for every scatterplot problem?
☐ Did I name the type of association (positive, negative, none)?
☐ Did I make predictions using the Desmos equation when asked?
