class 11

Math

Algebra

Statistics

For two data sets, each of size 5, the variances are given to be 4 and 5 and the corresponding means are given to be 2 and 4, respectively. The variance of the combined data set is

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The following table gives the distribution of the life time of $400$ neon lamps:

Find the mean deviation from the median for the following data: Size:, 10, 11, 12, 14, 15 Frequency:, 2, 3, 8, 3, 4

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While calculating eh mean and variance of 10 readings, a student wrongly used the reading of 52 for the correct reading 25. He obtained the mean and variance as 45 and 16 respectively. Find the correct mean and the variance.

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Find the mean and standard deviation using short-cut method

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If the mean of $25$ observations is $27$ and each observation is decreased by $7$, what will be the new mean ?