Measures of location and spread (T2)

Question 1

What is a measure of location?

Answer 1

A single value which describes a position in a data set

Question 2

What is a measure of central tendency?

Answer 2

The single value describes the centre of the data

Question 3

How do you calculate the mode?

Answer 3

The most common number

Question 4

How do you calculate the median?

Answer 4

The middle value

Question 5

How do you calculate the mean?

Answer 5

Sum of all numbers/ amount of numbers

Question 6

How do you calculate the mean in a given frequency table?

Answer 6

Sum of the frequencies

Question 7

When is the mode used?

Answer 7

When data is qualitative or quantitative with either a single mode or two modes

Question 8

What does bimodal mean?

Answer 8

When something has 2 modes

Question 9

How useful is the mode?

Answer 9

Not very informative if each value only occurs once

Question 10

When is the median used?

Answer 10

For quantitative data

Question 11

How useful is the median?

Answer 11

It is used when there are extreme values - as they do not affect the median

Question 12

When is the mean used?

Answer 12

Used for quantitative data & uses all the pieces of data

Question 13

How useful is the mean?

Answer 13

It gives a true measure of the data

However it is affected by extreme values

Question 14

How does the median split the data?

Answer 14

Into two equal (50%) halves

Question 15

What else can be calculated with the median?

Answer 15

The location of quartiles and percentiles

Question 16

Where is the lower quartile?

Answer 16

One-quarter of the way through the data set

Question 17

Where is the upper quartile?

Answer 17

Three-quarters of the way through the data set

Question 18

What are percentiles?

Answer 18

They split the data set into 100 parts

The 10th percentile lies one-tenth of the way through the data

Question 19

How do you find the lower quartile for discrete data?

Answer 19

Divide n by 4 and find the nearest whole number

Question 20

How do you find the upper quartile for discrete data?

Answer 20

Find 3/4 of n and find the nearest whole number

Question 21

What is interpolation?

Answer 21

You are assuming that the data values are evenly distributed within each class

Question 22

When is interpolation used?

Answer 22

When data is presented in a grouped frequency table interpolation is used to estimate the median, quartiles and percentiles

Question 23

For grouped continuous data, how do you calculate the lower quartile?

Answer 23

Q1 = n/4th data value

Question 24

For grouped continuous data, how do you calculate the median/Q2?

Answer 24

Q2 = n/2th data value

Question 25

For grouped continuous data, how do you calculate the upper quartile?

Answer 25

Q3 = 3n/4th data value

Question 26

What is a measure of spread?

Answer 26

A measure of how spread out the data

Question 27

What are the two simple measures of spread?

Answer 27

- Range | - IQR

Question 28

What is the range?

Answer 28

The difference between the largest & smallest values in the data set

Question 29

What is the IQR?

Answer 29

The Interquartile Range The difference between the UQ and LQ

Question 30

How useful is the range?

Answer 30

Takes into account all videos Can be affected by extreme values

Question 31

How useful is the IQR?

Answer 31

Not affected by extreme values Only takes into account middle 50% of the data

Question 32

What is the interceptile range?

Answer 32

The difference between the values for two given percentiles

Question 33

What data is usually used in the interceptile range?

Answer 33

the 10th to the 90th interpercentile is often used since it is not affected by extreme values but still considers 80% of the data