Statistics: Topic B-Data presentation and processing

What is a frequency table?

A table that shows how often each value or category occurs in a dataset.

What is a grouped frequency table?

A table where data is grouped into class intervals with corresponding frequencies.

What is a class interval?

A range of values used to group continuous data.

What is a class width?

The difference between the upper and lower boundaries of a class interval.

What is a class boundary?

The exact value separating class intervals, used to remove gaps between classes.

What is a tally chart?

A method of recording frequencies using tally marks.

What are advantages of a tally chart?

Quick to record data; easy to convert into frequencies.

What are disadvantages of a tally chart?

Not suitable for large datasets; can become difficult to read.

What is a bar chart?

A diagram using separated bars to represent frequencies of categorical or discrete data.

What are advantages of a bar chart?

Easy to interpret; useful for comparing categories.

What are disadvantages of a bar chart?

Not suitable for continuous data; can oversimplify complex data.

What is a dual bar chart?

A bar chart that compares two sets of data side by side.

What are advantages of a dual bar chart?

Allows direct comparison; clearly shows differences between groups.

What are disadvantages of a dual bar chart?

Can become cluttered; harder to interpret with many categories.

What is a pie chart?

A circular chart divided into sectors representing proportions of a whole.

What is the formula for a pie chart sector angle?

Angle = (frequency ÷ total) × 360

What are advantages of a pie chart?

Shows proportions clearly; useful for visual comparisons.

What are disadvantages of a pie chart?

Difficult to compare similar sizes; not suitable for large datasets.

What is a pictogram?

A chart that uses pictures or symbols to represent data.

What are advantages of a pictogram?

Visually appealing; easy to understand.

What are disadvantages of a pictogram?

Can be misleading if symbols are unclear; not precise.

What is a line graph (time series)?

A graph showing how data changes over time using connected points.

What are advantages of a time series graph?

Shows trends over time; easy to identify patterns.

What are disadvantages of a time series graph?

Does not show exact values clearly; trends may be misinterpreted.

What is a scatter graph?

A graph that shows the relationship between two variables using plotted points.

What are advantages of a scatter graph?

Shows relationships clearly; identifies correlation.

What are disadvantages of a scatter graph?

Does not show causation; can be hard to interpret with many points.

What is meant by positive correlation?

As one variable increases, the other increases.

What is meant by negative correlation?

As one variable increases, the other decreases.

What is meant by no correlation?

There is no relationship between the variables.

What is a two-way table?

A table showing frequencies for two categorical variables.

What are advantages of a two-way table?

Organises data clearly; allows comparison between categories.

What are disadvantages of a two-way table?

Can be complex; may require totals to interpret fully.

What is the mean?

The sum of all values divided by the number of values.

What is the formula for the mean from a frequency table?

Mean = (Σfx ÷ Σf)

What are advantages of the mean?

Uses all data values; useful for further calculations.

What are disadvantages of the mean?

Affected by outliers; not suitable for skewed data.

What is the median?

The middle value when data is arranged in order.

What are advantages of the median?

Not affected by outliers; suitable for skewed data.

What are disadvantages of the median?

Does not use all values; less useful for further calculations.

What is the mode?

The most frequent value in a dataset.

What are advantages of the mode?

Easy to identify; useful for categorical data.

What are disadvantages of the mode?

May not be unique; does not use all data.

What is the range?

The difference between the highest and lowest values.

What are advantages of the range?

Simple to calculate; gives a quick measure of spread.

What are disadvantages of the range?

Affected by outliers; does not show distribution.

What is an outlier?

A value that is significantly different from the rest of the data.

What is a stem-and-leaf diagram?

A diagram that splits data into stems and leaves to show distribution.

What are advantages of a stem-and-leaf diagram?

Shows all data values; displays distribution clearly.

What are disadvantages of a stem-and-leaf diagram?

Not suitable for large datasets; can be time-consuming.

What is a back-to-back stem-and-leaf diagram?

A diagram comparing two datasets using a shared stem.

What are advantages of a back-to-back stem-and-leaf diagram?

Allows direct comparison; shows distribution clearly.

What are disadvantages of a back-to-back stem-and-leaf diagram?

Can be confusing; not suitable for large datasets.

What is data processing?

Organising and transforming raw data into a usable form.

What is misleading data presentation?

When graphs or charts distort data to give a false impression.

What are causes of misleading graphs?

Unequal scales; missing data or distorted axes.

What is a frequency polygon?

A graph formed by joining midpoints of class intervals.

What are advantages of a frequency polygon?

Shows distribution shape; useful for comparing datasets.

What are disadvantages of a frequency polygon?

Less precise than histograms; depends on grouped data.