Chapter 4

Question 1

What is the mode?

Answer 1

The value that occurs most often

Question 2

What is the median?

Answer 2

The middle number in a list after the numbers have be put in order

Question 3

How is the mean worked out?

Answer 3

By adding up all the numbers then dividing it by how many numbers there are

Question 4

When discrete data are given in a frequency table what is the mode?

Answer 4

The one with the highest frequency

Question 5

When information is presented in a table of grouped data, what is the modal class?

Answer 5

The class with the largest frequency

Question 6

What are two ways of estimating the median?

Answer 6

Using the mid-point of a cumulative frequency diagram

Using interpolation

Question 7

What can an estimated mean be found from?

Answer 7

A grouped set of data using the formula

The sum of frequency ✖️ mid-point ➗ the sum of the frequency

Question 8

How is the weighted mean of a set of data given?

Answer 8

Using , The sum of w ✖️ X ➗ the sum of w

Where w is the weight given to each X variable

Question 9

How do you work out the range?

Answer 9

Largest value - smallest value

Question 10

What is the lower quartile?

Answer 10

The value such that one quarter (25%) of the values are less than or equal to it

Question 11

What is the upper quartile?

Answer 11

The value such that three quarters (75%) of the values are less than or equal to it

Question 12

How do you work out the IQR?

Answer 12

Upper quartile - lower quartile

Question 13

A set of data is divided into 10 equal parts to form what?

Answer 13

Percentiles

Question 14

When the set of data is divided into 10 equal parts, what are they called?

Answer 14

Deciles

Question 15

What does a box plot represent?

Answer 15

Important features of the data: the maximum and minimum values, the median, and the upper and lower quartile so

Question 16

In a pox plot, when is it negatively skewed?

Answer 16

If the median is closer the the upper quartile than the lower quartile

Question 17

In a box plot, when is it positively skewed?

Answer 17

If the medium is closer to the lower quartile than it is to the upper quartile

Question 18

In a box plot, when is it symmetrical?

Answer 18

If the median is equidistant from both the upper and lower quartile so

Question 19

In a box plot, what is an outlier?

Answer 19

Any value that is more than 1.5 times the IQR below the lower quartile or more than 1.5 times the IQR above the upper quartile

Question 20

What is the variance?

Answer 20

A measure or dispersion of spread

Question 21

What is the standard deviation?

Answer 21

The square root of the variance

Question 22

What does a full comparison between data sets need?

Answer 22

A measure of central tendency (an average)
A measure of dispersion or spread (IQR or range)
Skewness

Question 23

How do you work out standardised scores?

Answer 23

Score - mean ➗ standard deviation

Question 24

How do you work out the index number?

Answer 24

Current price ➗ base year price X 100

Question 25

How do you work out the chain base index number?

Answer 25

Current price ➗ previous years price X 100

Question 26

How do you work out the weighted index number?

Answer 26

Current weighted mean price ➗ base year weighted mean price X 100

Question 27

What is an average?

Answer 27

A single value used to describe a set of data