Week 4 solutions | Complete Solution

Levine : Page 111
Question 3.11,
The file Sedans contains the overall miles per gallon (MPG) of 2015 midsized sedans:
26    38    26    30    24    26    28    28    24    26    24    39
32    23    22    24    28    37    31    40    25    25    33    30
a. Compute the mean, median and mode.
b. Compute the variance, standard deviation, range, coefficient of variation, and Z scores.
c. Are the data skewed? If so how?
d. Compare the results of (a) through (c) to those of Problem 3.12 (a) through (c) that refer to the miles per gallon of small SUVs.
Question 312
a.
                        MPG

Mean                    23.15
Median                22.5
Minimum                21
Maximum                28
Range                    7
Variance                3.8184
Standard Deviation            1.9541
Coèff. Of variation            8.44%
Skewness                0.9427
Kurtosis                0.3998
Count                    20

b.

MPG            Z            MPG                Z
    26            1.4585            22            -0.5885
    22            -0.5885        21            -1.1003
    24            0.4350            22            -0.5885
    22            -0.5885        21            -1.1003
    26            1.4585            24            0.4350
    21            -1.1003        23            -0.0768
    24            0.4350            23            -0.0768
    25            0.9467            22            -0.5885
    28            2.4820            21            -1.1003
    24            0.4350            22            -0.5885

c. Since the mean MPG is greater than the median and the skewness statistic is positive, the distribution of MPG is right -or positive – skewed.

Levin: Page 118
Question 3.27,
The following is a set of data from a sample of n =7:
    12    7    4    9    0    7    3
a. Compute the first quartile (Q ₁), the third (Q ₃), and the interquartile range.
b. List the five-number summary.
c. Construct a boxplot and describe its shape.
d. Compare your answer in (c) with that from problem 3.3 (d) on page 110. Discuss.
Question 3.3 (d) on page 110.
d. Describe the shape of the data set.
Ghauri: Are decisions in business based on models? Give an example.