To understand the terms data, Array, Frequency, Mean, Mode and Mean.
To understand how to find the mean of grouped and ungrouped data.
To learn how to find the mode of given set of observation.
To learn how to find the median of ungrouped data.
To understand bar graphs and Histogram.
To understand the term probability and learn how to find the probability of an event.
DATA:A collection of numerical figures giving some particular type of information is called data.Example: The marks obtained by 10 students in a class test (out of 50) are:24, 43, 49, 38, 36, 36, 31, 40, 42, 15.Raw data: Data obtained in original form is known as raw data. Data given in above example is raw data.ARRAY:Arranging the data in ascending or descending order is known as array. Like in above example on arranging the above data in ascending order will be as:15, 23, 31, 36, 36, 38, 40, 42, 43, 49.It is known as array.TABULATION OF DATA:Arranging the data in form of table is known as tabulation of data.OBSERVATION:Each numerical figure in a data is called observation.FREQUENCY OF AN OBSERVATION:The number of times a particular observation occurs is called its frequency. In above example 36 occurs two times so its frequency is 2.STATISTICS:Statistics deals with the collection, presentation, analysis and interpretation of numerical data.MEAN OF UNGROUPED DATA:\[\text{Mean:}\,\,\frac{\text{Sum of the given observations}}{\text{No}\text{. of given observations}}\]Example: Find the mean of the numbers7, 6, 8, 9, 5, 4, 3, 7, 8, 2Solution: Sum of the given numbers = 7 + 6 + 8 + 9 + 5 + 4 + 3 + 7 + 8 + 2 = 59No. of given observation = 10\[\text{Mean}=\frac{59}{10}=5.9\]MEAN OF TABULATED DATA:If the frequency of \[n\] observation \[{{x}_{1}},{{x}_{2}},{{x}_{3}}........{{x}_{n}}\] are \[{{f}_{1}},{{f}_{2}},{{f}_{3}}.........{{f}_{n}}\] respectively then\[\text{Mean}=\frac{({{f}_{1}}{{x}_{1}}+{{f}_{2}}{{x}_{2}}+{{f}_{3}}{{x}_{3}}.....{{f}_{x}}{{x}_{n}})}{({{f}_{1}}+{{f}_{2}}+{{f}_{3}}.....{{f}_{n}})}=\frac{\Sigma ({{f}_{i}}\times {{x}_{i}})}{\Sigma {{f}_{i}}}\]\[\Sigma =\]Greek letter showing summationExample: The following table shows the weight of 15 workers in a factory.
