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Errors:
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1. A continuous variable can never be
measured with perfect finances because of certain habit and practices, method
of measurements etc.
2. Measurements are usually recorded to the
nearest units i.e. inch, pound, k.g etc.
3. They are therefore seldom exact, mostly
they are approximate, “the difference between the measured value and the true
value” however small it may be is called the error of measurements. e.g. if a
student’s weight is recorded as 60 kg (correct the nearest k.g) is true
weight infect lies between 59.5 kg and 60.5 kg. These there is the difference
between the measured value and the true value.
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Saturday, 29 October 2016
Errors:
Wednesday, 26 October 2016
Kinds of Constant
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Kinds
of Constant
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1.
Arbitrary
constants غیر مطلق مقدار
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2.
Absolute
constants مطلق مقدار
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Definition:
A constant is called
arbitrary constant if it has fixed value in a particular values in different
problems.
Denoted:
a, b, c…….
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Definition:
These are the quantities
which have the same value in all problems.
Examples:
1,2,3,4 are known as absolute constant.
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ایسی
مقداریں جو ایک ہی سوال کے سوال اپنی قیمت نہیں بدلتیں البتہ مختلف سوالات کے
دوران مختلف قیمتیں اختیار کر سکتی ہیں۔
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ایسی مقداریں جو کسی حالت میں
بھی اپنی قیمت نہ بدلیں مثلاً 15 ، -4/5، -1/2
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Note:
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1.
Variable X,Y,…. Are also called “Unknown
quantities”
2.
Constant a,b,c…. are also called “known
quantities”
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Constant:
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Constant:
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Definition1:
A measureable
quantity which can assume one and only one value is known as constant.
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Definition2:
A quantity which does
not change in a problem is called constant.
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Examples:
1.
Value
of g = 9.8m / sec2
2.
Value
of
3.
Value
of e = 2.7183
A
constant is usually denoted by first letters of alphabets A,B,C,D etc.
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Variable: Kinds of Variables:
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Variable:
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Definition:
“A characteristic which changes from one individual to another
is called a variable”.
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Kinds of Variables:
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1.
Discrete variable
2.
Continuous variable
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3.
Quantitative variable
4.
Quantitative variable
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1.
Discrete variable
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2.
Continuous variable
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Definition1:
A variable that can assumed only
specified values between a set of a values that is the values are taken by
jumps, is called discrete variables.
Definition2:
A discrete variable takes on values
which are integers or whole numbers”
Examples:
1.
Number of pages in a book.
2.
Number of rooms in a house.
3.
Price
4.
Income
5.
Saving
6.
Consumption
7.
Number of children in family can
be 0,1,2… but cannot be 2.5 or 3.84
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Definition:
“A
variable that can assume any value either fractional or integral between two
specified limits is called continuous variables”.
Examples:
1.
Heights and weights are students.
2.
Speed of a car or jumps.
3.
Temperature.
4.
Rain fall.
5.
Weight of a person.
6.
Height of a plant.
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Quantitative
variable
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Qualitative variable
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Definition:
“A characteristics whose change is
expressed numerically is called quantitative variable”
Examples:
Heights, weights, age , income etc.
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Definition:
“A
non-numerical characteristic which vary in quality is called qualitative
variable or attribute”.
The
data determined from a qualitative variable are called qualitative data.
Examples:
Education,
poverty, sex, beauty
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Observation:
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Observation:
Definition;
“In statistics, numerical measure of
some condition is called an observation.”
The
work of statistics may be called statistical work. The statistical work
starts with a set of observations. The
observations may be the wages of workers in factories, the number of
accidents per day on the roads and so on.
Thus
we start with observations.
Observations are the take off point for
statistical work.
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