Question

can any one fast tell me all about statistics of state board...!!its like about mean median and mode it's really very urgent tomorrow is my paper please give me fast answers

Answer 1

there are three types of mean.
1.direct method
2.Assumed mean.
3.step deviation.

direct method formula is,
sigmafixi/sigmafi

Assumed method formula is,
a+sigmafidi/sigmafi

step deviation formula is
a+h×sigmafiui/sigmafi
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median = l+[n/2-cf/f]×h
where l is lower limit of median class
n is number of observation
f is frequency of median class
cf is cumulative frequency of previous class and h is class size of median class

to find median class you have to see observation number that is n and then divide it by 2 i.e. n/2
whatever will be the value of n/2, see in which class it is located and that particular class will be your median class.
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mode= l+(f1-f0/2f1-f0-f2)×h
where l is lower limit of modal class
h is length of modal class
f1 is frequency of modal class
f2 is frequency of next class
f0 is frequency of previous class.

modal class will be the class with maximum frequency

in case where only number are given and mode is asked,
mode will be the number which is repeated the maximum time in the given data.