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Consider the following statements: 1.Th...

Consider the following statements:
1.The algebraic sum of deviations of a set of values from their arithmetic mean is always zero.
2 Arithmetic mean `gt` median `gt` mode for a symmetric distribution
Which of the above statements are corrects?

A

A) 1only

B

B) 2only

C

C) Both 1 and 2

D

D) Neither I nor 2

Text Solution

AI Generated Solution

The correct Answer is:
To determine which of the given statements is correct, we will analyze each statement step by step. ### Statement 1: The algebraic sum of deviations of a set of values from their arithmetic mean is always zero. 1. **Definition of Arithmetic Mean**: The arithmetic mean (denoted as \( \bar{x} \)) of a set of values \( x_1, x_2, \ldots, x_n \) is calculated as: \[ \bar{x} = \frac{1}{n} \sum_{i=1}^{n} x_i \] 2. **Sum of Deviations**: We need to find the sum of deviations from the mean: \[ A = \sum_{i=1}^{n} (x_i - \bar{x}) \] 3. **Expanding the Sum**: We can expand the sum: \[ A = \sum_{i=1}^{n} x_i - \sum_{i=1}^{n} \bar{x} \] Since \( \bar{x} \) is constant for all \( n \) observations, we can rewrite the second term: \[ A = \sum_{i=1}^{n} x_i - n \cdot \bar{x} \] 4. **Substituting the Mean**: From the definition of the mean, we know that: \[ n \cdot \bar{x} = \sum_{i=1}^{n} x_i \] Therefore, substituting this into our equation for \( A \): \[ A = \sum_{i=1}^{n} x_i - \sum_{i=1}^{n} x_i = 0 \] 5. **Conclusion for Statement 1**: The algebraic sum of deviations from the arithmetic mean is indeed always zero. Thus, Statement 1 is **correct**. ### Statement 2: Arithmetic mean > Median > Mode for a symmetric distribution. 1. **Understanding Symmetric Distribution**: In a symmetric distribution, the mean, median, and mode are all equal. This means: \[ \text{Mean} = \text{Median} = \text{Mode} \] 2. **Analyzing the Inequality**: The statement suggests that the arithmetic mean is greater than the median, and the median is greater than the mode. However, since all three measures are equal in a symmetric distribution, this inequality does not hold. 3. **Conclusion for Statement 2**: Therefore, Statement 2 is **incorrect**. ### Final Conclusion: - **Statement 1** is correct. - **Statement 2** is incorrect. Thus, the answer is that only the first statement is correct.
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Knowledge Check

  • Consider the following statements: 1. The algebraic sum of deviations of a set of values from their arithmetic mean is always zero. 2. Arithmetic mean gt Median gt Mode for a symmetric distribution. Which of the above statements is/are correct?

    A
    1 only
    B
    2 only
    C
    Both 1 and 2
    D
    Neither 1 nor 2
  • The algebraic sum of the deviations of a set of value of a data from their mean is

    A
    ` gt0`
    B
    0
    C
    `lt0`
    D
    none
  • Sum of deviations of different values from arithmetic mean is always equal to:

    A
    zero
    B
    one
    C
    less than one
    D
    more then one
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