AnswersCR - Algebra 2 26-27 - S2Designing a Study

Standard Deviation Answers

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1
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The data set on the right represents .

A
a sample of the population
B
the population
2
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Which formula should be used to calculate the variance?

Answer:

sigma^2 = sum(x - mu)^2 / n

3

What is the variance?

Answer:

32

4

Question text not available

Answers:
Blank 1:standard deviations
Blank 2:mean
5

The z-score is the number of [___] a data value is away from the [___].

Answer:

mean

6

What is the variance?

Answers:
Selection 1:864
Selection 2:29.4
7

A contractor records the areas, in square feet, of several houses in a neighborhood to determine data about the neighborhood. Which formula should be used to calculate the standard deviation?

A
Option
B
Option
C
Option
D
Option
8

Which of the following represents the numerator in the calculation of variance and standard deviation?

A
(225)2 + (–425)2 + (–275)2 + (325)2 + (75)2 + (–75)2 = 423,750
B
(650)2 + (–150)2 + (–600)2 + (250)2 + (150)2 + (–300)2 = 980,000
C
(250)2 + (–400)2 + (–250)2 + (350)2 + (100)2 + (–50)2 = 420,000
9

Using the formula below, calculate the z-score for the listed data points.

Answers:
Blank 1:-1.95
Blank 2:0.05
Blank 3:0.8
10

z1 = [___]

Answer:

-1.95

11

Given that z = –2 and z = –1, which of the following do you know?

Question illustration
A
The variance is 10.
B
The standard deviation is 30.
C
The mean is 80.
D
The median is 40.
E
The data point x = 20 is 2 standard deviations from the mean.
F
The data point x = 50 is 1 standard deviation from the mean.
G
The data point x = 45 has a z-value of 1.5.
12

The data value x exists in two data sets: A and B. The mean is equal for both data sets. If the standard deviation for set A is greater than the standard deviation for set B, which is true for zx for set A?

A
It is equal to zx for set B.
B
It is less than zx for set B.
C
It is greater than zx for set B.
13

A set of data has a high-value outlier. How do you expect the standard deviation to change when the outlier is removed? Would the result be different if the data had a low-value outlier instead? Explain.

Answer:

The standard deviation will decrease when the outlier is removed. Standard deviation represents the spread of data from the mean. Removing a high-value outlier decreases the spread of data from the mean. Removing a low-value outlier also decreases the spread of data from the mean. In both cases, the standard deviation decreases.

14

What is the standard deviation?

Answer not available
15

Why does the formula use “n – 1” in the denominator?

A
The data is a sample and is expected to be more dispersed from the mean.
B
The data is a sample and is expected to be less dispersed from the mean.
C
The data is a population and is expected to be more dispersed from the mean.
D
The data is a population and is expected to be less dispersed from the mean.
16

What is the variance?

Answer:

84000

17

What is the standard deviation, rounded to the nearest whole number?

Answer:

290

18

z5 = [___]

Answer:

0.05

19

Check each of the components below that you included in your response.

A
The standard deviation will decrease when the outlier is removed.
B
Standard deviation represents the spread of data from the mean.
C
Removing a high-value outlier decreases the spread of data from the mean.
D
Removing a low-value outlier decreases the spread of data from the mean.
E
In both cases the standard deviation decreases.
20

z6.5 = [___]

Answer:

0.8

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