STAAR Practice Test #3 TEKS 4 and 12 Name:________________________

STAAR Practice Test #3
Name:________________________
TEKS 4 and 12 (Correlation Coefficient)
Block:_________ Date:__________
1. (4B) The scatterplot shows the number of visitors to a beach each day and the high
temperature in degrees Fahrenheit for that day. Based on this scatterplot, which statement
appears to be true?
A There is a nonlinear correlation between the high temperature and the number of visitors to
the beach.
B When the high temperature is above 100°F, fewer than 150 visitors are expected at the
beach.
C There is no correlation between the high temperature and the number of visitors to the
beach.
D When the high temperature is between 75°F and 90°F, more than 120 visitors are expected
at the beach.
2. (12D) The first five figures in a pattern are shown below.
3. (12B) A city employee paints curbs in parking lots and replaces
Each figure is made up of identical circles. If the pattern
road signs. It takes 0.5 hour to paint a parking lot curb and 2.5 hours
continues, which expression can be used to find the number of
to replace a road sign. The function below can be used to find c, the
circles that make up Figure n?
number of parking lot curbs the employee paints when he replaces r
road signs in a 40-hour workweek.
A. 𝑛2 + 2𝑛
B. 𝑛2 + 2
C. 2𝑛2 + 1
D. 2𝑛2 + 𝑛
If the employee painted 20 curbs in one week, how many road signs
did he replace that week?
F 20
G 30
H0
2
J 12
3
4. (12B) The function 𝐿 = 0.8𝑇 2 models the relationship
5. (12B) If 𝑓(𝑥) = (𝑥 − 3) + 4 and𝑔(𝑥) = 𝑥 + 2, which
between L, the length in feet of a pendulum, and T, the period in
seconds of the pendulum. Which value is closest to the period in
seconds for a pendulum that is 30 ft long?
statement is true?
F 5.4
F f(−2) = g(−3)
G 4.9
H 6.8
J 6.1
G f(0) = g(−1)
H f(8) = g(3)
J f(2) = g(1)
6. (12A) Which representation does not show y as a function of x?
7. (12C) Write the first 4 terms of the sequence defined by the
8. (12E) For altitudes up to 36,000 feet, the relationship between
recursive rule: f(1) = 6 , f(n) = f(n − 1) + 8 , for each whole
number n greater than 1.
ground temperature and atmospheric temperature can be described
by the formula 𝑡 = −0.0035𝑎 + 𝑔, in which t is the atmospheric
temperature in degrees Fahrenheit, a is the altitude, in feet, at which
the atmospheric temperature is measured, and g is the ground
temperature in degrees Fahrenheit. Determine the altitude in feet
when t is -27.5 degrees and g is 60 degrees .
9. (12A) The mapping below represents y as a quadratic
10. (12D) Find the indicated term of the given sequence.
function of x. Which representation shows the same
relationship between x and y?
1, 8, 64, …; 7th term
11. (12D) Find the indicated term of the given sequence.
3, -12, 48, …; 7th term
12. (12D) Find the indicated term of the given sequence.
–2, –4, –6, –8, –10, …; 9th term
13. (12D) Seats in a concert hall are arranged in the pattern
shown. If every seat in the first 12 rows is filled, what is the
total revenue from those seats if each seat was $25?
15. (12A) Use the vertical line test to determine whether or not
each graph below represents function.
17. (12B) During the cold winter months the owner at a
ski resort studied the monthly sales figures for his hot
chocolate sales and notices a positive correlation to the
number of broken legs from falls!. He is horrified! He
decides to immediately close down his ski resort. Do you
agree with his decision?
14. (12B) The graph of f  x    x 2  4x  1 is below.
Find the value of f  x  when x  0. and CIRCLE it on the
graph below.
16. (12D) In Yellowstone National Park, they are trying to
increase the moose population. Currently there are 51
moose in the park. They hope to increase the population
by 2 moose each year. Predict the population on the 42nd
year.
18. (12D) Tai wrote the sequence -2, 5, 12, 19 . . . . .
What is the function rule?
A.
B.
C.
D.
𝑓(𝑛) = 7𝑛 − 7
𝑓(𝑛) = 7𝑛 − 9
𝑓(𝑛) = 4𝑛 − 7
𝑓(𝑛) = 4𝑛 − 9
19. (4A) Which graph below has a correlation coefficient close to 1?
20. (4A) Using the data below, estimate the correlation
coefficient.
A. 0.912
B. -0.997
C. 0.977
D. 1
22. (4B) A group of biologists is studying the population
of wolves and the population of deer in a particular region.
The biologists compared the populations each month for 2
years. After analyzing the data, the biologists found that as
the population of wolves increases, the population of deer
decreases. What can be said about this situation?
21. Which of the following are not functions?
A. 1, 2, 4, 5
B. 2, 5, 6
C. 3, 4, 6
D. 3, 6
23. (4B) The manager of an ice cream shop studies its
monthly sales figures and notices a positive correlation
between the average air temperature and how much ice
cream they sell on any given day. Which statement below
is false?
A. There is no real correlation in this situation.
A. The two variables are ice cream sales and average air
temperatures.
B. The cause of the increase in the deer population is
that the wolves are eating all the deer.
B. It is likely that warmer air temperatures cause an
increase in ice cream sales.
C. There is a correlation between the population of the
wolves and the population of deer, but it is uncertain
what it is.
C. It is doubtful that increased ice cream sales cause an
increase in air temperatures.
D. The decline in the deer population is causing more
wolves to be born and increasing their population.
D. There is a weak correlation between the number of ice
creams sold and the warmer temperatures.
Answer Key for Test #3
1
2
3
D
A
J
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
J
F
J
6, 14, 22,30
25,000
D
262,144
12,288
-18
$6750
1
A
133
No
B
A
B
D
C
D