Q8 of 35 Page 371

Find the mean and variance for the following frequency distributions in Exercises.

Presenting the data in the tabular form, we get



We know that Mean,


Where N =


∴


We know that Variance, σ2 =


∴ σ2 = (1/50) × 6600 = 132


Ans. Mean = 27 and Variance = 132


More from this chapter

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6

Find the mean and standard deviation using short-cut method.

 7

Find the mean and variance for the following frequency distributions in Exercises.

 9

Find the mean, variance and standard deviation using short-cut method

 10

The diameters of circles (in mm) drawn in a design are given below:


Calculate the standard deviation and mean diameter of the circles.


[Hint: First make the data continuous by making the classes as 32.5-36.5, 36.5-40.5,


40.5-44.5, 44.5 - 48.5, 48.5 - 52.5 and then proceed.]