# Statistics For Class 10

Statistics is a branch of mathematics that deals with the collection, organization, interpretation of data, which draws out the general conclusion about a set of data from a sample of the given data.

Generally the data is represented in a pictorial format, which represent the ungrouped data, also called the central tendency, namely mean, median and mode.

Mean of Grouped Data-

The mean of observations is the sum of the values of all the observations divided by the total number of observations.

Consider observation to be $x_{1}, x_{2}, x_{3}, ……, x_{n}$ and their respective frequencies be $f_{1}, f_{2}, f_{3}, ……, f_{n}$ then this means observation is given as-

$\overline{x}= \frac{f_{1}x_{1} + f_{2} x_{2} + f_{3} x_{3} +……+ f_{n}x_{n} }{f_{1} + f_{2} + f_{3} + ……. + f_{n}}$<

#### Practise This Question

The ratio of corresponding sides for the pair of triangles whose construction is given as follows :
Triangle ABC of dimesions AB=4cm,BC= 5 cm and ∠B= 60o.
A ray BX is drawn from B making an acute angle with AB.
5 points B1,B2,B3,B4 and B5 are located on the ray such that BB1=B1B2=B2B3=B3B4=B4B5.
B4 is joined to A and a line parallel to B4A is drawn through B5 to intersect the extended line AB at A'.
Another line is drawn through A' parallel to AC, intersecting the extended line BC at C'. Find the ratio of the corresponding sides of ΔABC and ΔABC.