Question

HOW TO PREPARE CHAPTER STATISTICS TODAY IS MY TEST
PLS TELL ME IMPORTANT ABOUT STATISTICS AND ALO EXPLAIN IT TO ME PLSSSS

Answer 1

CBSE Class 10 Mathematics
Revision Notes
CHAPTER 14
STATISTICS
1. Mean of Grouped Data
2. Mode of Grouped Data
3. Median of Grouped Data
4. Graphical Representation of CF
5. Miscellaneous Questions
1. Mean : The mean for grouped data can be found by :
(i) The direct method =
(ii) The assumed mean method
Where a = Provisional mean
(iii) The step deviation method
2. Mode : The mode for the grouped data can be found by using the formula :
= lower limit of the modal class.
= frequency of the modal class.
= frequency of the preceding class of the modal class.
= frequency of the succeeding class of the modal class.
h = size of the class interval.
Modal class - class interval with highest frequency.
3. Median : Median of continuous series is:
(i) term (if number of terms are odd)
(ii) (if number of terms are even]
(iii) The median for the grouped data can be found by using the formula :
= lower limit of the median class.
n = number of observations.
Cf = cumulative frequency of class interval preceding the median class.
f = frequency of median class.
h = class size.
4.Empirical Formula : Mode = 3 median - 2 mean.
5.Cumulative frequency curve or an Ogive :
(i) Ogive is the graphical representation of the cumulative frequency distribution.
(ii) Less than type Ogive :
• Construct a cumulative frequency table.
• Mark the upper class limit on the x-axis.
(iii) More than type Ogive :
• Construct a frequency table.
• Mark the lower class limit on the x-axis.
(iv) To obtain the median of frequency distribution from the graph :
• Locate point of intersection of less than type Ogive and more than type Ogive :
Draw a perpendicular from this point on x-axis.
• The point at which it cuts the x-axis gives us the median.