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Find the mean, variance and standard deviation for the data:
227, 235, 255, 269, 292, 299, 312, 321, 333, 348.
Concept: undefined >> undefined
Find the mean, variance and standard deviation for the data 15, 22, 27, 11, 9, 21, 14, 9.
Concept: undefined >> undefined
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The variance of 20 observations is 5. If each observation is multiplied by 2, find the variance of the resulting observations.
Concept: undefined >> undefined
The variance of 15 observations is 4. If each observation is increased by 9, find the variance of the resulting observations.
Concept: undefined >> undefined
The mean and standard deviation of 6 observations are 8 and 4 respectively. If each observation is multiplied by 3, find the new mean and new standard deviation of the resulting observations.
Concept: undefined >> undefined
The mean and variance of 8 observations are 9 and 9.25 respectively. If six of the observations are 6, 7, 10, 12, 12 and 13, find the remaining two observations.
Concept: undefined >> undefined
For a group of 200 candidates, the mean and standard deviations of scores were found to be 40 and 15 respectively. Later on it was discovered that the scores of 43 and 35 were misread as 34 and 53 respectively. Find the correct mean and standard deviation.
Concept: undefined >> undefined
The mean and standard deviation of 100 observations were calculated as 40 and 5.1 respectively by a student who took by mistake 50 instead of 40 for one observation. What are the correct mean and standard deviation?
Concept: undefined >> undefined
The mean and standard deviation of 20 observations are found to be 10 and 2 respectively. On rechecking it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation in each of the following cases:
(i) If wrong item is omitted
(ii) if it is replaced by 12.
Concept: undefined >> undefined
The mean and standard deviation of a group of 100 observations were found to be 20 and 3 respectively. Later on it was found that three observations were incorrect, which were recorded as 21, 21 and 18. Find the mean and standard deviation if the incorrect observations were omitted.
Concept: undefined >> undefined
Show that the two formulae for the standard deviation of ungrouped data
\[\sigma = \sqrt{\frac{1}{n} \sum \left( x_i - X \right)^2_{}}\] and
\[\sigma' = \sqrt{\frac{1}{n} \sum x_i^2 - X^2_{}}\] are equivalent, where \[X = \frac{1}{n}\sum_{} x_i\]
Concept: undefined >> undefined
Find the standard deviation for the following distribution:
| x : | 4.5 | 14.5 | 24.5 | 34.5 | 44.5 | 54.5 | 64.5 |
| f : | 1 | 5 | 12 | 22 | 17 | 9 | 4 |
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{5^x - 1}{\sqrt{4 + x} - 2}\]
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{\log \left( 1 + x \right)}{3^x - 1}\]
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{a^x + a^{- x} - 2}{x^2}\]
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{a^{mx} - 1}{b^{nx} - 1}, n \neq 0\]
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{a^x + b^x - 2}{x}\]
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{9^x - 2 . 6^x + 4^x}{x^2}\]
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{8^x - 4^x - 2^x + 1}{x^2}\]
Concept: undefined >> undefined
\[\lim_{x \to 0} \frac{a^{mx} - b^{nx}}{x}\]
Concept: undefined >> undefined
