In: Statistics and Probability
97, 147, 115, 135, 105, 78, 68, 100, 102, 117, 146, 77, 127, 87, 137, 109, 56, 91, 95, 150, 94, 100, 112, 114, 128, 112, 99, 107, 56, 121, 113, 150, 89, 119, 123, 134
Answer the following questions:
1) Calculate the following statistics for the data (original data):
a) the mean
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b) the median
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c) the standard deviation
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2) Rescale the original data using the transformation Y=X/14. For the transformed data in Y, calculate the following statistics:
a) the mean
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b) the median
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c) the standard deviation
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3) Use your answers in 1) and 2), which of the three statistics you calculated satisfies that “the statistic of the transformed data is the same as the transformed statistic of the original data”: [Hint: the transformed mean of the original data is the mean of the original data/14]
a) None of them
b) Only the mean
c) Only the median
d) Only the standard deviation
e) Only the mean and median
f) Only the mean and standard deviation
g) Only the median and standard deviation
h) All of them
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4) Shift the original data using the transformation U=X+14. For the transformed data U, calculate the following statistics:
a) the mean
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b) the median
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c) the standard deviation
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5) Use your answers in 1) and 4), which of the three statistics you calculated satisfies that “the statistic of the transformed data is the same as the transformed statistic of the original data”: [Hint: the transformed mean of the original data is the mean of the original data + 14]
a) None of them
b) Only the mean
c) Only the median
d) Only the standard deviation
e) Only the mean and median
f) Only the mean and standard deviation
g) Only the median and standard deviation
h) All of them
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6) Transform the original data using the transformation V = √X. For the transformed data V, calculate the following statistics:
a) the mean
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b) the median
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c) the standard deviation
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7) Use your answers in 1) and 6), which of the three statistics you calculated satisfies that “the statistic of the transformed data is the same as the transformed statistic of the original data”: [Hint: the transformed mean of the original data is: log(mean of the original data)] [Use 4 decimals when you compare]
a) None of them
b) Only the mean
c) Only the median
d) Only the standard deviation
e) Only the mean and median
f) Only the mean and standard deviation
g) Only the median and standard deviation
h) All of them
( 1 )
Mean :
Mean=Sum of terms / Number of terms
= 3910 / 36
= 108.6111
Median :
Ordering the data from least to greatest, we get:
56 56 68 77 78 87 89 91 94 95 97 99 100 100 102 105 107 109 112 112 113 114 115 117 119 121 123 127 128 134 135 137 146 147 150 150
As you can see, we do not have just one middle number but we have a pair of middle numbers, so the median is the average of these two numbers:
Median = ( 109+112) / 2 = 110.5
Standard deviation :
Create the following table.
data | data-mean | (data - mean)2 |
97 | -11.6111 | 134.81764321 |
147 | 38.3889 | 1473.70764321 |
115 | 6.3889 | 40.81804321 |
135 | 26.3889 | 696.37404321 |
105 | -3.6111 | 13.04004321 |
78 | -30.6111 | 937.03944321 |
68 | -40.6111 | 1649.26144321 |
100 | -8.6111 | 74.15104321 |
102 | -6.6111 | 43.70664321 |
117 | 8.3889 | 70.37364321 |
146 | 37.3889 | 1397.92984321 |
77 | -31.6111 | 999.26164321 |
127 | 18.3889 | 338.15164321 |
87 | -21.6111 | 467.03964321 |
137 | 28.3889 | 805.92964321 |
109 | 0.38890000000001 | 0.15124321000001 |
56 | -52.6111 | 2767.92784321 |
91 | -17.6111 | 310.15084321 |
95 | -13.6111 | 185.26204321 |
150 | 41.3889 | 1713.04104321 |
94 | -14.6111 | 213.48424321 |
100 | -8.6111 | 74.15104321 |
112 | 3.3889 | 11.48464321 |
114 | 5.3889 | 29.04024321 |
128 | 19.3889 | 375.92944321 |
112 | 3.3889 | 11.48464321 |
99 | -9.6111 | 92.37324321 |
107 | -1.6111 | 2.59564321 |
56 | -52.6111 | 2767.92784321 |
121 | 12.3889 | 153.48484321 |
113 | 4.3889 | 19.26244321 |
150 | 41.3889 | 1713.04104321 |
89 | -19.6111 | 384.59524321 |
119 | 10.3889 | 107.92924321 |
123 | 14.3889 | 207.04044321 |
134 | 25.3889 | 644.59624321 |
Find the sum of numbers in the last column to get.
∑(xi−X bar)2 = 20926.5556