Question 12 Marks
Explain 'population' giving illustrations.
Answer
View full question & answer→self practice
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Question 22 Marks
What is meant by Two dimensional graph ?
Answer
View full question & answer→- Geometric symbols are used to construct two-dimensional graphs.
- This graph can show two dimensions simultaneously.
- Such symbols include circles and squares.
- Like,
Question 32 Marks
Give brief information about tabulation.
Answer
View full question & answer→The required information is extracted separately from the total information collected.
That information is organized in a specific format. This process is called tabulation.
A table with as many boxes as necessary is prepared for it.
The table is given the title of the table by arranging the structure of rows and columns to accommodate the information collected.
Question 42 Marks
The marks of seven students of Std. 9 in Mathematics are as under. Find their moderator.
Answer
View full question & answer→70, 75, 72, 65, 68, 80, 67
- Arranging scores in ascending order:
- Here, there are a total of 7 observations. So n = 7, which is an even integer.
- Now, placing the value of observation in M = (n + 1) / 2,,
- Thus, the value of M will be equal to the fourth observation.
- The fourth observation is 70.
- Therefore, the average of the students' marks in mathematics is 70.
Question 52 Marks
Below are the marks obtained by the seven students in the science subject? Find the mean.
Answer
View full question & answer→62, 68, 42, 56, 57, 36, 50
$\sum \mathrm{x}_{\mathrm{i}}$ = $\mathrm{x}_{\mathrm{1}}$ + $\mathrm{x}_{\mathrm{2}}$ + $\mathrm{x}_{\mathrm{3}}$ + $\mathrm{x}_{\mathrm{4}}$ + $\mathrm{x}_{\mathrm{5}}$ + $\mathrm{x}_{\mathrm{6}}$ + $\mathrm{x}_{\mathrm{7}}$
= 62 + 68 + 42 + 56 + 57 + 36 + 50
= 371
Now, $\bar{x}$ = $\frac{\sum x_1}{n}$ = $\frac{371}{7}$ = 53
∴ Mean= 53
$\sum \mathrm{x}_{\mathrm{i}}$ = $\mathrm{x}_{\mathrm{1}}$ + $\mathrm{x}_{\mathrm{2}}$ + $\mathrm{x}_{\mathrm{3}}$ + $\mathrm{x}_{\mathrm{4}}$ + $\mathrm{x}_{\mathrm{5}}$ + $\mathrm{x}_{\mathrm{6}}$ + $\mathrm{x}_{\mathrm{7}}$
= 62 + 68 + 42 + 56 + 57 + 36 + 50
= 371
Now, $\bar{x}$ = $\frac{\sum x_1}{n}$ = $\frac{371}{7}$ = 53
∴ Mean= 53
Question 62 Marks
Explain the aggregate.
Answer
View full question & answer→- Primary and / or secondary statistics are obtained for any study.
- All these statistics are compiled under different units.
- The set of all units is called the study population.
- As such, the total population of Ahmadabad metropolis is called aggregate.
- All the students studying in standard nine in any one year in the state of Gujarat are called population.
- Population does not mean population.
Question 72 Marks
Below are the height figures of the five students. Find its mean.
Answer
View full question & answer→130, 120, 115, 118, 122
$\sum \mathrm{x}_{\mathrm{i}}$ = $\mathrm{x}_1$ + $\mathrm{x}_2$ + $\mathrm{x}_3$ + $\mathrm{x}_4$ + $\mathrm{x}_5$
= 130 + 10 + 1 15 + 118 + 122
= 605
Now, $\bar{\mathrm{x}}$ = $\frac{\sum x_i}{n}$; where $\bar{\mathrm{x}}$ is the mean
= $\frac{605}{5}$
=121
∴ Mean= 121
$\sum \mathrm{x}_{\mathrm{i}}$ = $\mathrm{x}_1$ + $\mathrm{x}_2$ + $\mathrm{x}_3$ + $\mathrm{x}_4$ + $\mathrm{x}_5$
= 130 + 10 + 1 15 + 118 + 122
= 605
Now, $\bar{\mathrm{x}}$ = $\frac{\sum x_i}{n}$; where $\bar{\mathrm{x}}$ is the mean
= $\frac{605}{5}$
=121
∴ Mean= 121
Question 82 Marks
What is statistics?
Answer
View full question & answer→- There are natural and man-made elements on the earth's surface.
- Information on the regional distribution of these elements is called 'geographic information'.
- Man-made details include population distribution, its density, statistics of industrial or agricultural products, etc., and natural elements include climate, minerals, animals, etc.
- Statistical information can be obtained about all these elements.
- Such information is called data.
Question 92 Marks
Where are the sources of statistics?
Answer
(2) The person conducting the study / experiment sometimes uses information prepared by someone else.
Information obtained from other sources is called secondary data.
View full question & answer→- Statistics can be obtained in two main ways:
(2) The person conducting the study / experiment sometimes uses information prepared by someone else.
Information obtained from other sources is called secondary data.