True or False? In a stem-and-leaf diagram, the stems are written horizontally and the leaves are written vertically (in order)

False. In a stem-and-leaf diagram, the stems are written vertically and the leaves are written horizontally (in order).

How do you find the median value of a data set from a stem-and-leaf diagram?

To find the median value from a stem-and-leaf diagram, you can cross off a pair of values (one from each end, highest and lowest) at a time until the middle value is found.

True or False? The highest value in a data set will be the first data item (leaf) in the last row (stem).

False. The highest value in a data set will be the last data item (leaf) in the last row (stem).

In the stem-and-leaf diagram below, what would be an appropriate key ? Adult Height (cm) 15 0 1 6 9 16 0 1 2 2 3 5 7 8 9 17 2 3 5 5 6 18 0 3

An appropriate key for the stem-and-leaf diagram would be to have two digits as the stem, representing the hundreds and tens columns, and a single digit as the leaf, representing the ones column. E.g. Key: 15 | 0 represents 150 cm.

How do you record a tally in groups of five?

Draw a vertical line for each of the first four items, then draw the fifth as a diagonal line across those four. Counting then carries on in fresh groups of five.

What is a frequency table ?

A frequency table records how many times each item appears in a set of data. It is usually built from a tally chart by totalling the marks in each row.

Why is it easier to make a tally chart first, rather than counting each category straight into a frequency table?

A tally lets you work through the data once , marking each item as you meet it. Counting each category separately means going back through the whole list again for every category.

True or False? The frequencies in the table should add up to the number of items collected.

True. Every item is counted exactly once, into exactly one row. If the frequencies do not add to the total collected, a mark has been missed or counted twice.

What does a bar chart show?

A bar chart represents discrete data, meaning data that can be counted. The horizontal axis shows the outcomes and the height of each bar gives the frequency .

True or False? The bars on a bar chart should touch each other.

False. Bars on a bar chart are drawn separated by gaps , and every bar is the same width . The gaps show that the categories are separate rather than running continuously into each other.

What is a dual or comparative bar chart?

A chart showing two data sets together, with the bars drawn in pairs for each outcome. Both sets measure the same variable, so they share a single scale.

How does a bar-line chart differ from a dual bar chart?

One data set is drawn as bars and the other as a line , so the two can use different scales . That lets it show two different variables at once, such as monthly rainfall alongside monthly temperature.

On a composite bar chart, how do you read the frequency for one type within a bar?

Read the height of that section alone , not the height of the whole bar. A section running from 600 up to 700 represents a frequency of 100, even though the bar reaches 700.

True or False? The overall height of a bar on a composite bar chart gives the total for that category.

True. The full height of the bar is the total frequency for that category. The sections stacked within it show how that total is divided between the different types.

How do you find a frequency from a pictogram ?

Use the key to find how many items one symbol stands for, then count the symbols. Part-symbols count proportionally, so half a symbol is worth half of that value.

What is a vertical line chart used for?

Showing numerical discrete data, especially where there are many different outcomes. The tallest line marks the mode, and how tightly the lines bunch together shows the spread.

At what point in the class interval are frequencies plotted in a frequency polygon ?

In a frequency polygon, frequencies are plotted at the midpoint of class intervals .

True or False? In a frequency polygon , you should always join the first point to the last one .

False. Do not join the first point to the last one . Also, unless one of the frequencies is 0, do not join the frequency polygon to the x-axis . A frequency polygon looks more like a series of line segments than a polygon!

How can you estimate the modal value from a frequency polygon ?

The modal class is the class with the highest frequency . An estimate of the modal value would be the midpoint of this class .

How can you estimate the range from a frequency polygon ?

The range can be estimated by subtracting the midpoint of the lowest class from the midpoint of the highest class .

In a frequency polygon , what does the height of each point represent?

The height of each point represents the frequency of that class .

True or False? Frequency polygons can only be used for discrete data.

False. Frequency polygons are used for continuous, grouped data.

A pie chart is drawn for a set of data where the total frequency is 180 . What do you do to the frequency of each item to find its angle for the pie chart?

If a pie chart is drawn for a set of data where the total frequency is 180 , you multiply the frequency of an item by 2 (i.e. 360 ÷ 180) to find the size of its angle on the pie chart.

In a pie chart, if you know that the angle 30° represents a frequency of 10 , how would you find the total frequency ?

In a pie chart, if an angle of 30° represents a frequency of 10, then you can find the total frequency by: dividing 10 by 30 to find how much 1° represents, then multiplying this by 360. Alternatively, you can see how many times 30° goes into 360° and then multiply this by 10.

How do you calculate the angles needed for a pie chart ?

To calculate the angles needed for a pie chart: Divide each frequency by the total frequency. Multiply each result by 360°. Alternatively: Divide 360° by the total frequency. Multiply each frequency by this number.

If you are given the angles in a pie chart and the total frequency , how do you calculate the individual frequencies ?

If you are given the angles in a pie chart and the total frequency , you can calculate the individual frequencies by doing the following: Divide each angle by 360°. Multiply by the total frequency. Alternatively: Divide the total frequency by 360. Multiply each angle by this number.

What is a time series graph ?

A time series graph is a graph that shows how a quantity (continuous data) changes over time . It is sometimes called a line graph .

What should the horizontal axis represent in a time series graph ?

The horizontal axis ( x -axis) in a time series graph should represent time .

True or False? Measurements in a time series graph should be taken at irregular time intervals .

False. Measurements should be taken at regular time intervals . I.e. The same amount of time in between each measurement.

What does a horizontal line in a time series graph indicate?

A horizontal line in a time series graph indicates no change (constant value) over that time period.

True or False? Points in a time series graph are connected by straight lines .

True. Points in a time series graph are connected by straight lines .

What does the steepest line in a time series graph represent?

The steepest line in a time series graph represents the greatest change (increase or decrease) over time .

What sorts of things should you look for when reading and interpreting statistical diagrams ?

When reading and interpreting statistical diagrams , you should look for: Keys Shading Axis labels The word "frequency" Any unusual or unexpected information mentioned

Define anomaly in the context of statistical diagrams.

An anomaly , otherwise known as an extreme value or outlier, is a data point that is significantly different from the rest of the data.

True or false? You may be asked to comment on aspects of a statistical diagram that could be misleading or incorrect .

True. You may be asked to comment on aspects of a statistical diagram that could be misleading or incorrect , such as uneven gaps in axis values or a missing key.

Define key in the context of statistical diagrams.

In the context of statistical diagrams, a key is a legend that explains the meaning of symbols, colours, or shading used in the diagram.

True or False? The purpose of comparing statistical diagrams is to identify and comment on differences or similarities in averages , spread , and unusual data values for the data sets represented by the diagrams.

True. The purpose of comparing statistical diagrams is to identify and comment on differences or similarities in averages , spread , and unusual data values for the data sets represented by the diagrams.

What should you consider when deciding which measures to compare in statistical diagrams?

When deciding which measures to compare in statistical diagrams, you should consider: Whether the mean, median or mode is the appropriate average to use. Whether the range or interquartile range is the appropriate measure of spread to use. Whether any assumptions or potential issues with the data could affect the reliability of the results and comparisons.

True or false? You should aim to make at least one pair of comments when comparing statistical diagrams.

False. You should aim to make at least two pairs of comments when comparing statistical diagrams: One pair should compare averages and comment on what this means in the context of the question. The other pair should compare spread and comment on what this means in the context of the question.

GCSEMathsEdexcelFoundationFlashcardsStatisticsStatistical Diagrams

Statistical Diagrams (Edexcel GCSE Maths: Foundation): Flashcards

Exam code: 1MA1

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FrontStem & Leaf Diagrams
True or False?
In a stem-and-leaf diagram, the stems are written horizontally and the leaves are written vertically (in order)

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Cards in this collection (42)

True or False?
In a stem-and-leaf diagram, the stems are written horizontally and the leaves are written vertically (in order)
False.
In a stem-and-leaf diagram, the stems are written vertically and the leaves are written horizontally (in order).
How do you find the median value of a data set from a stem-and-leaf diagram?
To find the median value from a stem-and-leaf diagram, you can cross off a pair of values (one from each end, highest and lowest) at a time until the middle value is found.
True or False?
The highest value in a data set will be the first data item (leaf) in the last row (stem).
False.
The highest value in a data set will be the last data item (leaf) in the last row (stem).
In the stem-and-leaf diagram below, what would be an appropriate key?

Adult Height (cm)
15
0 1 6 9
16
0 1 2 2 3 5 7 8 9
17
2 3 5 5 6
18
0 3
An appropriate key for the stem-and-leaf diagram would be to have two digits as the stem, representing the hundreds and tens columns, and a single digit as the leaf, representing the ones column.
E.g. Key: 15 | 0 represents 150 cm.
How do you record a tally in groups of five?
Draw a vertical line for each of the first four items, then draw the fifth as a diagonal line across those four.
Counting then carries on in fresh groups of five.
What is a frequency table?
A frequency table records how many times each item appears in a set of data.
It is usually built from a tally chart by totalling the marks in each row.
A tally shows two completed groups of five with two extra marks. Complete the frequency:
$5 + 5 + 2 =______$
The completed calculation is:
$5 + 5 + 2 = 12$
Count the completed groups in fives first, then add on the leftover marks.
Why is it easier to make a tally chart first, rather than counting each category straight into a frequency table?
A tally lets you work through the data once, marking each item as you meet it.
Counting each category separately means going back through the whole list again for every category.
True or False?
The frequencies in the table should add up to the number of items collected.
True.
Every item is counted exactly once, into exactly one row.
If the frequencies do not add to the total collected, a mark has been missed or counted twice.
What does a bar chart show?
A bar chart represents discrete data, meaning data that can be counted.
The horizontal axis shows the outcomes and the height of each bar gives the frequency.
True or False?
The bars on a bar chart should touch each other.
False.
Bars on a bar chart are drawn separated by gaps, and every bar is the same width.
The gaps show that the categories are separate rather than running continuously into each other.
What is a dual or comparative bar chart?
A chart showing two data sets together, with the bars drawn in pairs for each outcome.
Both sets measure the same variable, so they share a single scale.
How does a bar-line chart differ from a dual bar chart?
One data set is drawn as bars and the other as a line, so the two can use different scales.
That lets it show two different variables at once, such as monthly rainfall alongside monthly temperature.
On a composite bar chart, how do you read the frequency for one type within a bar?
Read the height of that section alone, not the height of the whole bar.
A section running from 600 up to 700 represents a frequency of 100, even though the bar reaches 700.
True or False?
The overall height of a bar on a composite bar chart gives the total for that category.
True.
The full height of the bar is the total frequency for that category.
The sections stacked within it show how that total is divided between the different types.
How do you find a frequency from a pictogram?
Use the key to find how many items one symbol stands for, then count the symbols.
Part-symbols count proportionally, so half a symbol is worth half of that value.
On a pictogram, one shoe symbol represents 2 students. Complete the frequency shown by one and a half symbols:
$2 + 1 =______$
The completed calculation is:
$2 + 1 = 3$
A whole symbol stands for 2 students and half a symbol for 1, giving 3 students.
What is a vertical line chart used for?
Showing numerical discrete data, especially where there are many different outcomes.
The tallest line marks the mode, and how tightly the lines bunch together shows the spread.
What is a frequency polygon?
A frequency polygon is a simple way of showing frequencies for continuous, grouped data that gives a quick guide to how frequencies change from one class to the next. An example is shown below.
At what point in the class interval are frequencies plotted in a frequency polygon?
In a frequency polygon, frequencies are plotted at the midpoint of class intervals.
True or False?
In a frequency polygon, you should always join the first point to the last one.
False.
Do not join the first point to the last one.
Also, unless one of the frequencies is 0, do not join the frequency polygon to the x-axis.
A frequency polygon looks more like a series of line segments than a polygon!
How can you estimate the modal value from a frequency polygon?
The modal class is the class with the highest frequency.
An estimate of the modal value would be the midpoint of this class.
How can you estimate the range from a frequency polygon?
The range can be estimated by subtracting the midpoint of the lowest class from the midpoint of the highest class.
In a frequency polygon, what does the height of each point represent?
The height of each point represents the frequency of that class.
True or False?
Frequency polygons can only be used for discrete data.
False.
Frequency polygons are used for continuous, grouped data.
A pie chart is drawn for a set of data where the total frequency is 180.
What do you do to the frequency of each item to find its angle for the pie chart?
If a pie chart is drawn for a set of data where the total frequency is 180, you multiply the frequency of an item by 2 (i.e. 360 ÷ 180) to find the size of its angle on the pie chart.
In a pie chart, if you know that the angle 30° represents a frequency of 10, how would you find the total frequency?
In a pie chart, if an angle of 30° represents a frequency of 10, then you can find the total frequency by:
- dividing 10 by 30 to find how much 1° represents,
- then multiplying this by 360.
Alternatively, you can see how many times 30° goes into 360° and then multiply this by 10.
How do you calculate the angles needed for a pie chart?
To calculate the angles needed for a pie chart:
- Divide each frequency by the total frequency.
- Multiply each result by 360°.
Alternatively:
- Divide 360° by the total frequency.
- Multiply each frequency by this number.
If you are given the angles in a pie chart and the total frequency, how do you calculate the individual frequencies?
If you are given the angles in a pie chart and the total frequency, you can calculate the individual frequencies by doing the following:
- Divide each angle by 360°.
- Multiply by the total frequency.
Alternatively:
- Divide the total frequency by 360.
- Multiply each angle by this number.
What is a time series graph?
A time series graph is a graph that shows how a quantity (continuous data) changes over time.
It is sometimes called a line graph.
What should the horizontal axis represent in a time series graph?
The horizontal axis (x-axis) in a time series graph should represent time.
True or False?
Measurements in a time series graph should be taken at irregular time intervals.
False.
Measurements should be taken at regular time intervals.
I.e. The same amount of time in between each measurement.
What does a horizontal line in a time series graph indicate?
A horizontal line in a time series graph indicates no change (constant value) over that time period.
True or False?
Points in a time series graph are connected by straight lines.
True.
Points in a time series graph are connected by straight lines.
What does the steepest line in a time series graph represent?
The steepest line in a time series graph represents the greatest change (increase or decrease) over time.
What sorts of things should you look for when reading and interpreting statistical diagrams?
When reading and interpreting statistical diagrams, you should look for:
- Keys
- Shading
- Axis labels
- The word "frequency"
- Any unusual or unexpected information mentioned
Define anomaly in the context of statistical diagrams.
An anomaly, otherwise known as an extreme value or outlier, is a data point that is significantly different from the rest of the data.
True or false?
You may be asked to comment on aspects of a statistical diagram that could be misleading or incorrect.
True.
You may be asked to comment on aspects of a statistical diagram that could be misleading or incorrect, such as uneven gaps in axis values or a missing key.
Define key in the context of statistical diagrams.
In the context of statistical diagrams, a key is a legend that explains the meaning of symbols, colours, or shading used in the diagram.
True or False?
The purpose of comparing statistical diagrams is to identify and comment on differences or similarities in averages, spread, and unusual data values for the data sets represented by the diagrams.
True.
The purpose of comparing statistical diagrams is to identify and comment on differences or similarities in averages, spread, and unusual data values for the data sets represented by the diagrams.
What should you consider when deciding which measures to compare in statistical diagrams?
When deciding which measures to compare in statistical diagrams, you should consider:
- Whether the mean, median or mode is the appropriate average to use.
- Whether the range or interquartile range is the appropriate measure of spread to use.
- Whether any assumptions or potential issues with the data could affect the reliability of the results and comparisons.
True or false?
You should aim to make at least one pair of comments when comparing statistical diagrams.
False.
You should aim to make at least two pairs of comments when comparing statistical diagrams:
- One pair should compare averages and comment on what this means in the context of the question.
- The other pair should compare spread and comment on what this means in the context of the question.

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	Adult Height (cm)
15	0 1 6 9
16	0 1 2 2 3 5 7 8 9
17	2 3 5 5 6
18	0 3