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Zorluk: OrtaMeasures of Dispersion and Position (Range, IQR, Standard Deviation, Percentiles)

Dataset SS consists of 10 distinct numerical values. Dataset TT is created by replacing the maximum value of Dataset SS with a number that is strictly greater than that maximum value, while all other 9 values remain unchanged. Which of the following statements comparing Dataset SS and Dataset TT must be true? Select all that apply.

  1. The range of Dataset TT is greater than the range of Dataset SS.Cevap
  2. The interquartile range (IQR) of Dataset TT is equal to the interquartile range of Dataset SS.Cevap
  3. C
    The standard deviation of Dataset TT is equal to the standard deviation of Dataset SS.
  4. D
    The median of Dataset TT is strictly greater than the median of Dataset SS.
  5. E
    The 75th percentile of Dataset TT is strictly greater than the 75th percentile of Dataset SS.

Cevap

The statements asserting that the range of Dataset TT is greater than the range of Dataset SS and that the interquartile range (IQR) of Dataset TT is equal to the interquartile range of Dataset SS are correct.
The statement regarding the range is correct because increasing the maximum value increases the difference between the maximum and minimum values. The statement regarding the interquartile range is correct because the 25th percentile (Q1Q_1) and 75th percentile (Q3Q_3) depend only on the first 8 ordered elements of a 10-element dataset, so changing the 10th element leaves Q1Q_1 and Q3Q_3 identical.

Adım Adım Çözüm

1
Analyze the impact on Range
Range(T)>Range(S)\text{Range}(T) > \text{Range}(S)
Range is defined as MaximumMinimum\text{Maximum} - \text{Minimum}. Since the minimum is unchanged and the maximum increases, the range must increase.
2
Analyze the impact on Interquartile Range (IQR)
IQR(T)=IQR(S)\text{IQR}(T) = \text{IQR}(S)
IQR is Q3Q1Q_3 - Q_1. For 10 ordered elements, Q1Q_1 and Q3Q_3 depend on the positions of the bottom 75% of the data. Modifying only the 10th (largest) element leaves Q1Q_1 and Q3Q_3 unchanged.
3
Analyze the impact on Median and Standard Deviation
Median is unchanged; Standard deviation increases.
The median depends on the 5th and 6th values, which are unaffected. Moving an extreme value further out increases distance from the mean, strictly increasing standard deviation.

Anahtar Kavram

Effect of outlier modification on measures of position (Q1,Q3Q_1, Q_3, Median) versus measures of dispersion (Range, Standard Deviation, IQR).
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