I.Com (Intermediate in Commerce) Statistics Syllabus

What is chronological classification?

Classification of data according to time, e.g. production figures arranged year by year or month by month.

What is geographical classification?

Classification of data according to place, region or location, e.g. population of different provinces.

Define tabulation of data.

Tabulation is the systematic arrangement of data into rows and columns of a table for easy comparison and analysis.

What are the main parts of a statistical table?

Table number, title, stub (row headings), caption/box-head (column headings), body, head-note, and footnote/source note.

What is the 'stub' of a table?

The stub is the left-hand column of a table containing the row headings that describe the contents of each row.

What is the 'caption' (box-head) of a table?

The caption is the heading of the columns, describing the data contained in each column.

State two main objectives of tabulation.

To present data in a compact, simplified form and to facilitate comparison, analysis and reference.

What is a frequency distribution?

A frequency distribution is a table showing how data values are distributed among different classes along with the frequency (number of items) in each class.

List the main steps in constructing a frequency distribution.

Find the range, decide the number of classes, determine the class interval, form the classes, and tally the observations to get frequencies.

How is the Range of data calculated?

Range = Largest value (maximum) − Smallest value (minimum).

How is the class interval (size of class) estimated?

Class interval (h) = Range ÷ Number of classes desired.

Define class frequency.

Class frequency is the number of observations or items that fall within a particular class.

What are class limits?

Class limits are the smallest (lower limit) and largest (upper limit) values that a class can contain, as written in the frequency table.

What are class boundaries (true limits)?

Class boundaries are the actual/true limits of a class with no gaps, found by adjusting the class limits to make classes continuous.

How are class boundaries obtained from class limits?

Subtract half the gap (d/2) from each lower limit and add half the gap to each upper limit, where d is the gap between the upper limit of one class and the lower limit of the next.

For classes 10–19 and 20–29, what are the boundaries of 10–19?

The gap is 1, so half-gap is 0.5; the boundaries are 9.5 to 19.5.

What is the class mark (mid-point) and how is it found?

The class mark is the central value of a class, found as (Lower class limit + Upper class limit) ÷ 2.

What is the difference between class limits and class boundaries?

Class limits are the stated values in the table (may have gaps); class boundaries are continuous true limits with no gaps, used for graphing and calculation.

Define cumulative frequency.

Cumulative frequency is the running total of frequencies obtained by successively adding the frequency of each class to the sum of frequencies of preceding classes.

What is a 'less than' cumulative frequency?

It is the total number of observations falling below the upper boundary of each class, accumulated from the lowest class upward.

What is a 'more than' cumulative frequency?

It is the total number of observations falling above the lower boundary of each class, accumulated from the highest class downward.

What is a bar chart (bar diagram)?

A bar chart represents data using rectangular bars of equal width whose lengths/heights are proportional to the values they represent.

What is the difference between a simple bar chart and a multiple bar chart?

A simple bar chart shows one variable with single bars; a multiple bar chart shows two or more related variables with grouped bars for comparison.

What is a component (sub-divided) bar chart?

A bar chart in which each bar is divided into parts/segments to show the components that make up the total.

What is a pie chart?

A pie chart is a circle divided into sectors, where each sector's angle is proportional to the value of the component it represents.

How is the angle of a sector in a pie chart calculated?

Angle = (Component value ÷ Total value) × 360°.

What is a histogram?

A histogram is a graph of a frequency distribution using adjacent rectangles drawn on class boundaries, with areas proportional to the class frequencies.

How does a histogram differ from a bar chart?

In a histogram bars are adjacent (no gaps) and drawn on class boundaries for continuous data; in a bar chart bars have gaps and represent discrete/categorical data.

What is a frequency polygon and how is it drawn?

A frequency polygon is a line graph of a frequency distribution made by plotting frequencies against class marks (mid-points) and joining the points with straight lines.

What is an Ogive (cumulative frequency curve)?

An Ogive is a graph obtained by plotting cumulative frequencies against the upper (or lower) class boundaries and joining the points with a smooth curve; it is used to read the median and quartiles.