Question

class 10th chapter 14 statistics maths formula​

Answer 1

CBSE Class 10 Maths Notes Chapter 14 Statistics

MEAN (AVERAGE): Mean [Ungrouped Data] – Mean of n observations, x1, x2, x3 … xn, is

Statistics Class 10 Notes Maths Chapter 14 1

MEAN [Grouped Data]: The mean for grouped data can be found by the following three methods:

(i) Direct Mean Method:

Statistics Class 10 Notes Maths Chapter 14 2

Class Mark = UpperClassLimit+LowerClassLimit2

Note: Frequency of a class is centred at its mid-point called class mark.

(ii) Assumed Mean Method: In this, an arbitrary mean ‘a’ is chosen which is called, ‘assumed mean’, somewhere in the middle of all the values of x.

Statistics Class 10 Notes Maths Chapter 14 3

…[where di = (xi – a)]

(iii) Step Deviation Method:

Statistics Class 10 Notes Maths Chapter 14 4

….. [where ui=dih , where h is a common divisor of di]

MEDIAN: Median is a measure of central tendency which gives the value of the middle-most observation in the data.

Statistics Class 10 Notes Maths Chapter 14 5

…where[l = Lower limit of median class; n = Number of observations; f = Frequency of median class; c.f. = Cumulative frequency of preceding class; h = Class size]

(iii) Representing a cumulative frequency distribution graphically as a cumulative frequency curve, or an ogive of the less than type and of the more than type. The median of grouped data can be obtained graphically as the x-coordinate of the point of intersection of the two ogives for this data.

Mode:

(i) Ungrouped Data: The value of the observation having maximum frequency is the mode.

(ii) Grouped Data:

Statistics Class 10 Notes Maths Chapter 14 6

…where[l = Lower limit of modal class; f1 = Frequency of modal class; f0 = Frequency of the class preceding the modal class; f2 = Frequency of the class succeeding the modal class; h = Size of class interval. c.f. = Cumulative frequency of preceding class; h = Class size]

Mode = 3 Median – 2 Mean

Median = Mode+2Mean3

Mean = 3Median−Mode2

Answer 2

Answer:

Mean(Direct Method) = Sigma fx/Sigma f

Mean(Assume mean method) = a + (Sigma fx/Sigma f)

Step Deviation method is not coming in Exams.

Mode = l + {(f1 - f0)×h}/{2f1 - f0 - f2}

Median = l + {n/2 - cf} × h/{f}