Unit 14

Question 1

Population

Answer 1

set of items that you are interested in

Question 2

Census

Answer 2

Survey of the whole population

Question 3

Sample

Answer 3

Smaller number of items from the whole population. A sample of at least 10% is considered to be a good sample

Question 4

How do you reduce bias

Answer 4

In order to recue bias, the sample must represent the whole population

Question 5

Random sample

Answer 5

In a random sample each item has the same chance of being chosen

Question 6

Strata

Answer 6

A population may divide into groups such as age range or gender. These groups are called strata

Question 7

What is a stratified sample

Answer 7

Number of people taken from each group is proportional to the group size

Question 8

What does cumulative frequency show

Answer 8

How many data values are less than or equal to the upper class boundary of each data class

Question 9

What is a cumulative frequency diagram

Answer 9

A cumulative frequency diagram has data values on the x-axis and cumulative frequency on the y axis

Question 10

How do you find the estimate for the median value

Answer 10

n
– th value
2

Question 11

How do you find the estimate for the lower quartile

Answer 11

n
- th value
4

Question 12

How do you find the estimate for the upper quartile

Answer 12

3n
— th value
4

Question 13

How do you find the interquartile range (IQR)

Answer 13

UQ - LQ

Question 14

How do you find the lower quartile for a set of n data value

Answer 14

(n + 1)
——– th
4

Question 15

How do you find the upper quartile for a set of n data values

Answer 15

3 (n+1)
——— th
4

Question 16

What does a box - plot display

Answer 16

A box plot sometimes known as a cat and whisker diagram displays a data set to show the median and quartiles

Question 17

What are comparative box plots

Answer 17

Comparative box plots are box plots for two different sets of data drawn on the same scale

Question 18

What is a histogram

Answer 18

A histogram is similar to a bar chart but is used to represent continuous data

Question 19

What does the area and height of each bar in a histogram represent

Answer 19

In a histogram the area of the bar represents the frequency

The height of each bar is frequency density

Question 20

How do u calculate frequency density

Answer 20

class width

Question 21

What does the interquartile range measure

Answer 21

The interquartile range measures the spread of the middle 50% of the data.

Question 22

How do you describe a data set

Answer 22

To describe a data set (or population) give a measure of average and a measure of spread.

Question 23

How do you compare data sets

Answer 23

Compare a measure of average and spread