LECTURE 3 Flashcards
What are graphs?
Charts that use points, lines, and curves to represent data.
What is the purpose of graphs?
Provide a visual representation of grouped quantitative data.
What are the features of graphs?
- Drawn on graph sheets 2. Require scales for x-axis and y-axis 3. Used for grouped data.
What is a histogram?
A graph that represents data classified by class intervals using continuous bars.
What is the key feature of a histogram?
No gaps between bars since classes are continuous.
What is represented on the x-axis of a histogram?
Class intervals.
What is represented on the y-axis of a histogram?
Frequencies.
What is a histogram used for?
Frequency distribution representation.
What is a frequency polygon?
A graph connecting class frequencies using dots and straight lines.
What is plotted on the x-axis of a frequency polygon?
Midpoints of class intervals.
What is plotted on the y-axis of a frequency polygon?
Frequencies.
How are the points connected in a frequency polygon?
By straight lines.
What is a frequency curve?
A graph where class frequencies are connected by a smooth, free-hand curve.
What is the difference between a frequency polygon and a frequency curve?
Frequency polygons use straight lines; frequency curves use smooth curves.
What are ogives?
Cumulative frequency curves.
What are the two types of ogives?
- Less than Ogive 2. More than Ogive.
What is a less than ogive?
A graph plotting cumulative frequencies against the upper class boundary.
What is a more than ogive?
A graph plotting cumulative frequencies against the lower class boundary.
What is the purpose of ogives?
Visualize cumulative frequency data and determine the median.
What is the process to draw a histogram?
- Plot class intervals on the x-axis 2. Draw bars where heights represent frequencies 3. Ensure no gaps between bars.
What is the process to draw a frequency polygon?
- Plot midpoints of class intervals on the x-axis 2. Plot corresponding frequencies on the y-axis 3. Connect the points with straight lines.
What is the process to draw a frequency curve?
- Plot midpoints of class intervals on the x-axis 2. Plot corresponding frequencies on the y-axis 3. Connect the points with a smooth curve.
What is the process to draw less than ogives?
Plot cumulative frequencies against the upper class boundary.
What is the process to draw more than ogives?
Plot cumulative frequencies against the lower class boundary.
What can be drawn using a histogram?
Frequency polygon, frequency curve, and frequency distribution.
Where do the less than and more than ogives intersect?
At the median.
To draw a frequency polygon, what is used on the x-axis?
Midpoints of class intervals.
In a frequency curve, points are joined by bits of straight lines. True or False?
False (They are joined by a smooth curve).
Histograms can be drawn for equal and unequal classes. True or False?
True.
What are the diagrams that can be drawn for a frequency distribution table?
Histogram, frequency polygon, frequency curve, and ogives.
