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#### Collection of data - Review

1 , 5, 6 ,5 ,8 ,7 ,5 ,10 ,0 , 2

1 ,2 , ,3,10 ,22, 8 ,7 ,9 ,15

The above are the marks obtain by the students of class 7 in math in dictation . The numerical figures are called data. Statistics is a branch of mathematically related with the collection of different thing which is shown by figures . It analysis the data. The data should be always shown proper order so that it will be easier to get the important and necessary information for which they are collected . The data are always arranged in ascending or descending order , which is known as a proper order.

The data which arranged properly are called arrayed data. If the data are not arranged properly then they are said raw data . Data are always can be present in a bar graph or in a line graph.

8 6 7 9 8 6 7 8

8 6 8 8 7 8 7 9

6 6 6 7 7 7 7 8

8 8 8 8 8 8 9 9

#### ( Arrayed Data)

Here ,

• Rs 6 is repeated three times. So , its frequency is 3.
• Rs 7 is repeated four times . So, its frequency is 4.
• Rs 8 is repeated seven times . So , its frequency is 7.
• Rs 9 is repeated two times . So , its frequency is 2.
 Wages (in Rs ) Tally marks Frequency 6 ||| 3 7 |||| 4 8 $$\enclose{horizontalstrike}{||||}$$ || 7 Total 14

The data and their frequencies can be shown in the table called frequency table . So, the above wages of 14workers in the frequency table . It is the system of showing frequencies by using diagonal lines grouped in five when each time five is reached , there is a horizontal line is drawn with the tally marks to make a group of five . For example :

 1 | 2 | | 3 ||| 4 |||| 5 $$\enclose{horizontalstrike}{||||}$$ 6 $$\enclose{horizontalstrike}{||||}$$ | 7 $$\enclose{horizontalstrike}{||||}$$ || 8 $$\enclose{horizontalstrike}{||||}$$ ||| 9 $$\enclose{horizontalstrike}{||||}$$ |||| 10 $$\enclose{horizontalstrike}{||||}$$ $$\enclose{horizontalstrike}{||||}$$

Bar graph

There are mainly two types of a bar graph . They are described below :

Simple bar graph : The data which is presented single or the graph which is drawn to present single type of data is called simple bar graph . In a simple bar, data are equally wide . The height of the bars represents the frequency at the data.

• Construct the bars of the same width and at equal distance.
• Decide how wide the bars will be and how much space you will leave between them.
• Choose a suitable scale to represent the whole data . Mention the frequencies in the y-axis.

Multiple bar graph : Multiple bar graph is drawn to or more than two related components of the given data.

Average ( or mean )

The single number which represents the central value of a set of data is known as average . It indicated or show the quality of the data . It is calculated by adding them together and dividing the sum by the number of data.

Average = $$\frac{Total sum of data}{Number of data}$$

If x is used to represent the data and n is used to represent the number of data , then,

Average = $$\frac{∑x}{n}$$

Here , the symbol '∑' means the summation of whole data.

Mean or average of ungrouped repeated data

Following are the steps given below to calculate the mean of ungrouped repeated data .

• Draw a table with 3 columns and Write down the items (x) in the first column .
• Write the corresponding frequency (f)of each item in the second column and find the produce of each item(x) and its frequency (f ) in the third (fx ) column.
• Find the total of column andfx column and divide the sum offx by the sum off , the quotient is the required means .

• The single number which represents the central value of a set of data is known as average .
•  The data which is presented single or the graph which is drawn to present single type of data is called simple bar graph
• Mean is calculated by Average = $$\frac{∑x}{n}$$ this formula.
.

#### Click on the questions below to reveal the answers

Solution:

Let's present the above data of 16 workers in frequency table:

 Wages () TallyMarks Frequency 60 ||| 3 70 |||| 4 80 |||| || 7 90 || 2 Total 16

0%

bar
arrayed
raw
frequency
• ### A ______ is drawn to show two or more related components of the given data.

simple bar graph
bar graph
multiple bar graph
timeline
• ### A ______ is drawn to present a single type of data.

bar graph
multiple bar graph
simple bar graph
timeline

frequency
data
mean
bar

bar graph
frequency
mean
data

## ASK ANY QUESTION ON Statistics

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