A purchasing agent for a trucking company is shopping for replacement tires for their trucks from two suppliers. The suppliers' prices are the same. However, Supplier A's tires have an average life of 60,000 miles with a standard deviation of 10,000 miles. Supplier B's tires have an average life of 60,000 miles with a standard deviation of 2,000 miles.

76.  A purchasing agent for a trucking company is shopping for replacement tires for their trucks from two suppliers.  The suppliers' prices are the same.  However, Supplier A's tires have an average life of 60,000 miles with a standard deviation of 10,000 miles.  Supplier B's tires have an average life of 60,000 miles with a standard deviation of 2,000 miles.

Which of the following statements is true?

A)  The two distributions of tire life are the same

B)  On average, Supplier A's tires have a longer life then Supplier B's tires

C)  The life of Supplier B's tire is more predictable than the life of Supplier A's tires

D)  The dispersion of Supplier A's tire life is less than the dispersion of Supplier B's tire life

Answer: C     

77.  The sum of the differences between sample observations and the sample mean is

A)  Zero

B)  The mean deviation

C)  The range

D)  The standard deviation

Answer: A       

78.  What disadvantage(s) are there of the mean deviation?

A)  Based on only two observations

B)  Based on deviations from the mean

C)  Uses absolute values, which are difficult to manipulate

D)  All of the above

Answer: C        

79.  Which of the following measures of dispersion are based on deviations from the mean?

A)  Variance

B)  Standard deviation

C)  Mean deviation

D)  All of the above

Answer: D       

 

80.  What is the relationship between the variance and the standard deviation?

A)  Variance is the square root of the standard deviation

B)  Variance is the square of the standard deviation

C)  Variance is twice the standard deviation

D)  No constant relationship between the variance and the standard deviation

81.  According to Chebyshev's Theorem, what percent of the observations lie within plus and minus 1.75 standard deviations of the mean?

A)  56%

B)  95%

C)  67%

D)  Cannot compute because it depends on the shape of the distribution

82.  What is the range for a sample of March electric bills amounts for all-electric homes of similar sizes (to the nearest dollar): $212, $191, $176, $129, $106, $92, $108, $109, $103, $121, $175 and $194.

A)  $100

B)  $130

C)  $120

D)  $112

83.  A survey of passengers on domestic flights revealed these miles:

 

What is the range (in miles)?

A)  2,499

B)  1,100

C)  2,400

D)  1,999

 

84.  Which measure of dispersion disregards the algebraic signs (plus and minus) of each difference between X and the mean?

A)  Standard deviation

B)  Mean deviation

C)  Arithmetic mean

D)  Variance

85.  The following are the weekly amounts of welfare payments made by the federal government to a sample of six families: $139, $136, $130, $136, $147 and $136.  What is the range?

A)  $0

B)  $14

C)  $52

D)  $17

 

86.  Measures of dispersion calculated from grouped data are

A)  Estimates

B)  Biased

C)  Means

D)  Skewed

87.  The ages of a sample of the typewriters used by the typists in the typing pool were organized into the following table:

 

What is the sample variance?

A)  About 10.2

B)  About 6.1

C)  About 14.0

D)  About 3.2

E)  None of the above

 

88.  The weights of a sample of crates ready for shipment to Laos are (in kilograms): 103, 97, 101, 106 and 103.  What is the mean deviation?

A)  0 kg

B)  6.9 kg

C)  102.0 kg

D)  2.4 kg

E)  9.0 kg

89.  The closing prices of a common stock have been 61.5, 62, 61.25, 60.875 and 61.5 for the past week.  What is the range?

A)  $1.250

B)  $1.750

C)  $1.125

D)  $1.875

90.  Ten experts rated a newly developed chocolate chip cookie on a scale of 1 to 50.  Their ratings were: 34, 35, 41, 28, 26, 29, 32, 36, 38 and 40.  What is the mean deviation?

A)  8.00

B)  4.12

C)  12.67

D)  0.75

                                        

 CLICK HERE TO GET THE ANSWER !!!!