Question

Compute the (sample) variance and standard deviation of the data sample. (Round your answers to two decimal places.)

−1, 7, 7, 5, 12

variance | 22 |

standard deviation | ? |

Answer #1

Solution :

Given that,

x |
x^{2} |

- 1 | 1 |

7 | 49 |

7 | 49 |

5 | 25 |

12 | 144 |

x
= 30 |
x^{2}
= 268 |

The sample variance S^{2}

S^{2} = (
x^{2} ) - ((
x )^{2} / n ) / 1 -n )

= ( 268 (- (30 )^{2} / 5 ) /4

^{ } = ( 268 -180 ) 4

=88 /4

= 22

The sample variance S^{2} = 22

The sample standard is S =
The sample variance S^{2}

= 22

= 4.6904

The sample standard is S = 4.69

A sample of 22 items provides a sample standard deviation of
6.
(a)
Compute the 90% confidence interval estimate of the population
variance. (Round your answers to two decimal places.)
________ to _________
(b)
Compute the 95% confidence interval estimate of the population
variance. (Round your answers to two decimal places.)
________ to _______
(c)
Compute the 95% confidence interval estimate of the population
standard deviation. (Round your answers to one decimal place.)
________ to _________

Find the range, mean, variance and standard deviation for the
given set of data. Round your answers to the nearest tenth.
3, 4, 7, 11, 12, 12, 15, 16

3.2 question 6
Find the sample variance and the standard deviation for the
following sample. Round the answers to at least two decimal places
as needed. 15 31 23 19 14 37 The sample variance is ___?
The sample standard deviation is___?

This data is from a sample. Calculate the mean,
standard deviation, and variance.
This data is from a sample. Calculate the mean,
standard deviation, and variance.
x
20.5
45.3
10.6
31.8
28.4
30.6
49.8
32.2
27.3
Please show the following answers to 2 decimal
places.
Sample Mean =
Sample Standard Deviation =
Sample Variance = (Please use the standard deviation
above for your calculation.)
Ooops - now you discover that the data was actually from a
population! So now you must...

Consider the data set:
34,49,27,15,50,57,31,39,27,51,62,42,42,36.
a. Compute the sample mean, the sample variance, and the sample
standard deviation of this data set. [Note: Round your answers to
four decimal places.]
b. Construct the five-point summary for this data set (i.e. find
its maximum, minimum, median, and quartiles) and sketch the
boxplot.
c. Are there any possible outliers in this data set?
d. Construct a Stem-and-Leaf plot.

This data is from a sample. Calculate the mean, standard
deviation, and variance. Suggestion: use technology. Round answers
to two decimal places.
x
32.5
34.8
49.7
45
18.1
35.2
42.6
10.6
20.8
Mean =
Standard Deviation =
Variance =
Ooops - now you discover that the data was actually from a
population! So now you must give the population standard
deviation.
Population Standard Deviation =
Question Help: Message Message instructor

Answers
Range
?
Variance
?
Standard deviation
?
Letter Grade
Percentage
Frequency #
Cumulative Frequency #
A
93–100
1
1
A-
90–92.9
1
2
B+
87–89.9
2
4
B
83–86.9
3
7
B-
80–82.9
5
12
C+
77–79.9
4
16
C
73–76.9
3
19
C-
70–72.9
1
20
D+
67–69.9
0
20
D
60–66.9
2
22
F
Below 59.9
1
23
5. Use the formulas for range, population variance, and
population standard deviation with the “Percentage Grade Total” to
complete...

Fill in this table to find the standard deviation for
this SAMPLE data.
Round your answer to two decimal places.
You must show all of your additional work in the box
below and in the table to earn credit.
DATA
300
205
203
90
84
120

Using the same data set as in 1, find the variance, standard
deviation, and range, using the formulas. Using the same data set
as in 1, find the variance, standard deviation, and range, using
the formulas. Show the formulas and intermediate steps. Round your
answers to the correct number of decimal places
data set 9, 2, 8, 2, -9, 5, 6, 2, -5, -9, 9, 4, 5, 5, -3, -1,
0

For the following set of 10 scores, compute the range, the
standard deviation, and the variance. 5, 7, 3, 4, 5, 6, 7, 2, 5,
3.
Range:
Standard deviation (3 digits after decimal point):
Variance (1 digit after decimal point):

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