1.1 Definition Of Statistic
statistic is the study of how to collect, organizes, analyze and interpret numerical information from data
1.2 Types Of Statistic
Descriptive Statistics - involve methods of organizing, picturing and summarizing information from data
Inferential Statistics - involve methods of using information from a sample to draw conclusions about the population.
1.3 Steps In Statistical Investigation
Collection Of Data
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Organization Of Data
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Presentation Of Data
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Analysis
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Interpretation Of Results
a) Collection Of Data
A structure of statistical investigation is based on a systematic collection of data. The data is classified into 2 groups
i) internal data
internal data area obtained from internal records related to operations of business organization such as production, source of income and expenditure, inventory, purchases and accounts
ii) eternal data
the external data are collected and purchased from external agencies. The external data could be either primary data or secondary data. The primary data are collected from 1st time and original, while secondary data are collected or published by some agencies
b) Organization Of Data
The collected data is a large mass of figures that needs to be organized. The collected data must be edited to rectify for any omissions, irrelevant answers and wrong computation. The edited data must be classified to suit further analysis
c) Presentation Of Data
The large data that are collected cannot be understand and analysis and quickly. Therefore, collected data needs to be presented in tabular or graphic form. This systematic order and graphical presentation helps for further analysis
d) Analysis Of Data
The analysis requires establishing the relationship between one or more variables. Analysis of data includes abstracting, summarization, conclusion and ect. With the help of statistical tools and techniques like measures o dispersion central tendency, correlation, variance analysis ect, analysis can be done
e) Interpretation Of Data
The interpretation requires deep insight of the subject. Interpretation involves drawing valid conclusions on the bases of the analysis of data. This work requires good experience and skill. This process is very important as conclusions of results are don based on interpretation.
1.4 Function Of Statistics
a) Present Fact In Simple Form
b) Reduces The Complexity Of Data
c) Facilitates Comparison
d) Testing Hypothesis
e) Forecasting
1.5 Categories Of Data
Primary Data
Secondary Data
The difference between each one is not really known
example : is the difference between "ok" and "unhappy" the same as the difference between "very happy" and " happy"?
Interval
Interval has values of equal intervals that mean something. For example, a thermometer migh have intervals of ten degrees.
Example :
Celsius Temperature
- 60°C and 50°C= 10°C . 80°C and 70°C= 10°C .
- But! Don't have a "True Zero"
Fahrenheit Temperature
IQ ( Intelligence Scale )
Ratio
Ratio exactly the same as the interval scale except that the zero on the scale means: Does not exist. For example, a weight of zero doesn't exist; an age of zero doesn't exist. On the other hand,, temperature is not ratio scale, because zero exists ( ie. zero on the celsius s
