Definitions [10]
Frequency:
The number of times a particular observation occurs.
Frequency Distribution:
A tabular arrangement of data showing the frequency of each observation or class.
The two values that bound a class interval.
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Lower limit: Smallest value of the class
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Upper limit: Largest value of the class
The difference between the highest and lowest observations.
Range = Highest value − Lowest value
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Inclusive form: Both lower and upper limits are included in the class.
(Example: 1–10, 11–20) -
Exclusive form: Lower limit is included, but upper limit is excluded.
(Example: 0–10, 10–20)
Statistics is the area of study dealing with the collection, presentation, and analysis of data as well as drawing meaningful conclusions from the data.
A collection of given facts or figures, usually expressed in numerical form.
Each group into which raw data is divided is called a class interval.
Data is a collection of facts, information, or observations, usually in numerical form.
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Example: The heights of all the children in your class.
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Example: The marks obtained by 20 students in a math test.
Raw Data is the information that you have just collected, and it is completely unsorted or unarranged. It's like a messy pile of clothes!
Example (Marks): Imagine a teacher writes the test marks of 15 students on the board:
72, 77, 67, 74, 82, 80, 66, 90, 78, 57, 56, 54, 74, 72, 92
This long list is Raw Data. It's hard to quickly tell who scored the highest or lowest mark.
Define the mean.
The mean is the value that is derived by summing all the values and dividing it by the number of observations.
`bar"x" = "Sum of observations"/"No. of observations"`
Formulae [2]
\[\text{Adjustment Factor}=\frac{1}{2}\text{(Lower limit of next class - Upper limit of previous class)}\]
\[\text{Frequency density}=\frac{\mathrm{Frequency}}{\text{Class width}}\]
