Interpreting Data

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Frequency Table

In many kinds of data, many values related to a parameter occur many times.

In a class of 30 students, many students may receive the same score in a test. Many students may have birthdays falling in the same month. Many students may come to school by a particular mode of transport. Many students may live in the same locality. We may like the same kind of food. We may like to know which is the most popular food or the number of students coming from the same locaclity. The frequency table helps us to tabulate such data.

The table lists out the various parameters and helps us tabulate the result in each individual case, which later can be summed to show the result. Several queries can be answered using the table. Many times in the lower classes, we can use pictures to represent the dat instead of numbers. For example instead of writing 5 (houses) we can actually draw simple pictures of houses as and when we are building the table.

Bar Graph

A Bar Graph is a visual depiction of the Frequency Table. Many times data presented visually is easier to grasp than just numbers. Each piece of numerical data is converted into a vertical rectangle (bar) where the height of the bar represents the number. The width of all the bars is kept same.

If the numbers are big, then they are &ldquo;scaled down&rdquo; using a common ratio and depicted within the bar graph. For instance in a graph comparing the student strength of several classes, 100 students may be represented by 1 unit on the bar graph.

An example is the comparison of the number of students who have scored in a particular range, in a particular test. The ranges may be in steps of 10 from 0-10, 11-20 etc upto 91-100. The bar graph will visually show the performance of the students in thagt test.

Joint Bar Graph

The joint bar graph is a modification of the bar graph. Hence the analysis of 2 tests can be represented as bars, coloured or shaded differently. This can help us compare the performance in more than 1 test visually from the same graph. It could also provide information on whether the performance from test 1 to test 2 has been an improvement or otherwise.

Histogram

Line Graph

A line graph is a modification of the bar graph. Here the width of a bar is reduced so that it is just like a vertical line. Imagine a line which joins the top of all the lines and the lines themselves are subbed out! The shape of this line can be interpreted in the context of the data.

The Line graph can also depict more than 1 line where each line represents the values related to a particular event. For example, the performance, of the students in a class, in 2 or more tests can be drawn on the same graph and conclusions drawn.

Pie Graph

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