The measurements (in m.m.) of the diameters of the heads of 107 screws are as given below :
Calculate the standard deviation.

The weights of a group of children at 6 month are given below: Find the standard deviation.

The diameters of circles (in mm) drawn in a design are given below : Calculate the standard deviation and mean diameter of the circles.

The length and breadth of three rectangles are a given below: 9 m and 6 m

The length and breadth of three rectangles are a given below: 17 m and 3m

The length and breadth of three rectangles are a given below: 4 m and 14 m

From a frequency distribution consisting of 18 observations, the mean and the standard deviation were found to be 7 and 4 respectively. But on comparison with the original data, it was found that a figure 12 was miscopied as 21 in calculations. Calculate the correct mean and standard deviation.

The instrument for the accurate measurement of the e.m.f. of a cell is:

Calculate the mean deviation about median age for the age distribution of 100 persons given below :

The diameter of a sphere is 14 m. The volume of this sphere is :