Standard Deviation

Question 1

The data set on the right represents .

Revolt · Accepted Answer

B: the population

Question 2

What is the variance?

Revolt · Accepted Answer

C: 864

Question 3

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?

Revolt · Accepted Answer

B: mc001-2.jpg

Question 4

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

Revolt · Accepted Answer

C: (250)2 + (–400)2 + (–250)2 + (350)2 + (100)2 + (–50)2 = 420,000

Question 5

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

Revolt · Accepted Answer

: -1.95; : 0.05; : 0.8

Question 6

z1 = [___]

Revolt · Accepted Answer

0

Question 7

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

Revolt · Accepted Answer

B: The standard deviation is 30.; C: The mean is 80.; 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.

Question 8

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?

Revolt · Accepted Answer

B: It is less than zx for set B.

Question 9

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.

Revolt · Accepted Answer

The standard deviation will decrease when the outlier is removed. Standard deviation represents the spread of data from the mean. Both highvalue and lowvalue outliers increase the spread of a data set. Therefore, removing either a highvalue or a lowvalue outlier decreases the spread from the mean, which results in a lower standard deviation.

Question 10

Which formula should be used to calculate the variance?

Revolt · Accepted Answer

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

Standard Deviation Answers

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