Introduction to Statistics — Unit test Answers

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Which equation describes the relationship between the variables in the table below?xy-11928146,561559,049

Question illustration
A
; each y-value is the previous y-value multiplied by 9.
Option A
B
; each y-value is the previous y-value plus 9 more than was added previously.
Option B
C
; each y-value is the previous y-value plus 9.
Option C
D
; each y-value is the previous y-value multiplied by another 9.
Option D
6

Ramon is graphing the function f(x) = 3(4)x. He begins by plotting the initial value. Which graph represents his initial step?

A
On a coordinate plane, the point (0, 3) is graphed.
Option A
B
On a coordinate plane, the point (0, 4) is graphed.
Option B
C
On a coordinate plane, the point (3, 0) is graphed.
Option C
D
On a coordinate plane, the point (4, 0) is graphed.
Option D
7

How would the graph change if the b value in the equation is decreased but remains greater than 1? Check all that apply.

A
The graph will begin at a lower point on the y-axis.
B
The graph will increase at a faster rate.
C
The graph will increase at a slower rate.
D
The y-values will continue to increase as x-increases.
E
The y-values will each be less than their corresponding x-values.
8

On a coordinate plane, an exponential function approaches y = 0 in quadrant 2 and curves up and increases in quadrant 1.

Question illustration
A
The domain includes all integers, and the range is y ≥ 0.
B
The domain includes all integers, and the range is y > 0.
C
The domain includes all real numbers, and the range is y ≥ 0.
D
The domain includes all real numbers, and the range is y > 0.
9

Which best describes the graph of the function f(x) = 4(1.5)x?

A
The graph passes through the point (0, 4), and for each increase of 1 in the x-values, the y-values increase by 1.5.
B
The graph passes through the point (0, 4), and for each increase of 1 in the x-values, the y-values increase by a factor of 1.5.
C
The graph passes through the point (0, 1.5), and for each increase of 1 in the x-values, the y-values increase by 4.
D
The graph passes through the point (0, 1.5), and for each increase of 1 in the x-values, the y-values increase by a factor of 4.
10

Several ordered pairs from a continuous exponential function are shown in the table.

Question illustration
A
The domain is the set of integers, and the range is y > 4.
B
The domain is the set of integers, and the range is y > 0.
C
The domain is the set of real numbers, and the range is y > 0.
D
The domain is the set of real numbers, and the range is y > 4.
11

Which graph shows exponential growth?

A
On a coordinate plane, a parabola opens up with vertex at (0, 0).
Option A
B
On a coordinate plane, a curve approaches y = 0 in quadrant 2 and curves up into quadrant 1.
Option B
C
On a coordinate plane, a straight line with positive slope crosses the y-axis at (negative 1, 0) and crosses the y-axis at (2, 0).
Option C
D
On a coordinate plane a curve opens down and to the right in quadrants 1 and 4. It crosses the x-axis at (1, 0).
Option D
12

Which is the graph of f(x) = (4)x?

Question illustration
A
Option
B
Option
C
Option
D
Option
16

Which is the graph of f(x) = 0.5(4)x?

A
On a coordinate plane, an exponential growth function approaches y = 0 in the second quadrant and goes through points (0, 1), (2, 8), (3, 32).
Option A
B
On a coordinate plane, an exponential growth function approaches y = 0 in the second quadrant and goes through points (0, 4), (1, 16), (2, 64).
Option B
C
On a coordinate plane, an exponential growth function approaches y = 0 in the second quadrant and goes through points (0, 1), (3, 8), (4, 16).
Option C
D
On a coordinate plane, an exponential growth function approaches y = 0 in the second quadrant and goes through points (0, 1), (1, 8), (2, 32).
Option D
18

A growth medium is inoculated with 1,000 bacteria, which grow at a rate of 15% each day. What is the population of the culture 6 days after inoculation?

A
y = 1,000(1.15)6; 2,313 bacteria
B
y = 1,000(1.15)7; 2,660 bacteria
C
y = 1,000(1.5)5; 7,594 bacteria
D
y = 1,000(1.5)6; 11,391 bacteria
19

Geraldine is asked to explain the limits on the range of an exponential equation using the function f(x) = 2x. She makes these two statements:1. As x increases infinitely, the y-values are continually doubled for each single increase in x.2. As x decreases infinitely, the y-values are continually halved for each single decrease in x.

A
Statement 1 is incorrect because the y-values are increased by 2, not doubled.
B
Statement 2 is incorrect because the y-values are doubled, not halved.
C
The conclusion is incorrect because the range is limited to the set of integers.
D
The conclusion is incorrect because the range is limited to the set of positive real numbers.
20

Which equation represents an exponential function with an initial value of 500?

A
f(x) = 100(5)x
B
f(x) = 100(x)5
C
f(x) = 500(2)x
D
f(x) = 500(x)2

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