Calculate mean deviation and standard deviation. Interpret the results so obtained of the following

frequency distribution:- 4+4+2=10

00-09………………………….6

10-19………………………….8

20-29…………………………10

30-39…………………………15

40-49…………………………25

50-59………………………....30

60-69…………………………21

70-79…………………………19

80-89…………………………14

90-99………………………….9

100-109……………………….5

Is zero an even number?

Because by definition,'an even number is a number divisible by two',or else a number multiple of 2.That means,0/2 =0 otherwise 0*2=0.Which leads to the question,Is zero an even number?Please answer.

What is the proof of theorem- If the angles subtended by the chords of a circle at the centre are equal, then chords are equal

Please hint to solve

ex.-8.1 q.9 Class 9

D E F are the mid points of the sides bc ca ab respectively of a ∆abc,Prove that BDEF is a parallelogram whose area is half that of ∆abc and area of ∆def=1/4(area of ∆abc)

Question 7

What is median???? 

Theorem 9.2

In triangle ABC, side AB is equally cut in three parts by points M and N .two line segments MP and NQ are parallel to BC and cuts side AC at point P and Q respectively.prove that point P and Q cut the side AC in three equal parts.