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For a set of ungrouped values the follow...

For a set of ungrouped values the following sums are found:
`" "n=15, sumx=480, sumx^(2)=15735`.
Find the standard deviation.

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To find the standard deviation for the given ungrouped data, we can use the formula for standard deviation: \[ \sigma = \sqrt{\frac{\sum x^2}{n} - \left(\frac{\sum x}{n}\right)^2} \] Where: - \( n \) is the number of observations, - \( \sum x \) is the sum of the observations, - \( \sum x^2 \) is the sum of the squares of the observations. Given: - \( n = 15 \) - \( \sum x = 480 \) - \( \sum x^2 = 15735 \) ### Step 1: Calculate \(\frac{\sum x^2}{n}\) First, we calculate \(\frac{\sum x^2}{n}\): \[ \frac{\sum x^2}{n} = \frac{15735}{15} \] Calculating this gives: \[ \frac{15735}{15} = 1049 \] ### Step 2: Calculate \(\frac{\sum x}{n}\) Next, we calculate \(\frac{\sum x}{n}\): \[ \frac{\sum x}{n} = \frac{480}{15} \] Calculating this gives: \[ \frac{480}{15} = 32 \] ### Step 3: Calculate \(\left(\frac{\sum x}{n}\right)^2\) Now, we square the result from Step 2: \[ \left(\frac{\sum x}{n}\right)^2 = 32^2 = 1024 \] ### Step 4: Substitute values into the standard deviation formula Now, we substitute the values into the standard deviation formula: \[ \sigma = \sqrt{1049 - 1024} \] Calculating this gives: \[ \sigma = \sqrt{25} \] ### Step 5: Calculate the final value of standard deviation Finally, we find the square root: \[ \sigma = 5 \] Thus, the standard deviation for the given data is \( 5 \). ### Summary of Steps: 1. Calculate \(\frac{\sum x^2}{n}\). 2. Calculate \(\frac{\sum x}{n}\). 3. Square the result from Step 2. 4. Substitute into the formula and simplify. 5. Take the square root to find the standard deviation.
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ICSE-MEASURES OF DISPERSION-EXERCISE 21 (b)
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