In: Statistics and Probability
Project Questions:
Apply the statistical techniques and completely describe your data
set for both variables in the light of following questions: Each
(X,Y) has 20 observations.
a. Discuss the types and level of measurement of the
variables in the data.
b. Prove that A.M>G. M>H.M (For both the
variables).
c. Estimate the values of Q3, D7 and P49 and Interpret
the results.
d. Compare Relative Dispersions of X and Y. Using (i)
Quartile Coefficient of Dispersion and (ii) Coefficient of
Variation.
e. Explain whether the above two measures in part (d)
provide the same information.
f. Which Variable is more consistent.
g. Discuss the shape of the variables X and Y using
results of Mean, Median and Mode.
h. Obtain skewness by Karl Pearson’s formula, For which
variable (X,Y) skewness is more sharp.
i. Obtain the Bowley’s coefficient of skewness. Is
there any change in the decision regarding the shape of the
variables?
j. Draw a scatter plot of the data.
k. Obtain Pearson’s coefficient of Correlation and
interpret the results.
l. Discuss what changes will there be on the value of
the correlation coefficient if we transform variables X (first
variable in the data) and Y (second variable in the data) using the
following expressions. will there be any change in the value of
rxy, if so then why or if not then why, please discuss.
u= 5x+46 and v=3y+2
X: Crime Rate (number of offences per million population)
Y: Expenditure (per capita expenditure on police)
X 45.5 52.3 56.6
60.3 64.2 67.6 70.5
73.2 75 78.1 79.8
82.3 83.1 84.9 85.6
88 92.3 94.3 95.3
96.8
Y 69 55 47
46 106 67 63
66 56 51 45
97 62 118 58
71 74 128 90 58
a).
X: Crime Rate (number of offences per million population)
Y: Expenditure (per capita expenditure on police)
X 45.5 52.3 56.6
60.3 64.2 67.6 70.5
73.2 75 78.1 79.8
82.3 83.1 84.9 85.6
88 92.3 94.3 95.3
96.8
Y 69 55 47
46 106 67 63
66 56 51 45
97 62 118 58
71 74 128 90 58
b).
X | Y | |
Arithmetic Mean = | 76.29 | 71.35 |
Geometric Mean = | 74.77 | 68.02 |
harmonic Mean = | 73.12 | 65.21 |
Clearly, AM > GM > HM for the variables
c).
X | Y | |
Q3 | 86.20 | 78.00 |
D7 | 85.11 | 71.90 |
P49 | 78.59 | 63.87 |
d).
For quartile deviation we use IQR = Q3-Q1
X | Y | |
Q3 | 86.20 | 78.00 |
Q1 | 66.75 | 55.75 |
IQR | 19.45 | 22.25 |
1.5*IQR | 29.18 | 33.38 |
Coefficient of variation= | 0.19 | 0.33 |
e).
The above two computations are both measures of dispersion and variation.
f). The one with less CV is more stable. X is more consistent
g).
X | Y | |
Mean | 76.29 | 71.35 |
Median | 78.95 | 64.50 |
Mode | #N/A | 58.00 |
Here, Mean > Median > Mode
Therefore, the distributions are Right skewed.
Please rate my answer and comment for doubt.