Representing Data

Question 1

What are the four types of data. Describe each

Answer 1

⭕️ Qualitative - not need to be expressed in numbers
⭕️ Quantitative - data expressed as numbers
⭕️ Discrete - can list values
⭕️ Continuous - must be rounded

Question 2

What is needed for a stem and leaf diagram

Answer 2

A key

Question 3

What are the positives of using a stem and leaf diagram

Answer 3

Raw data preserved
Data ordered
Length of line gives shape of each distribution
Easy to compare distributions

Question 4

When are grouped frequency tables used

Answer 4

If data widely spread

Question 5

What do the groups look like for discrete and continuous frequency tables

Answer 5

⭕️ Discrete - groups don’t overlap

⭕️ Continuous - < or greater than/equal sign

Question 6

What are the four key points for histograms

Answer 6

1. Bars must touch
2. FD on y axis
3. FD = f/CW
4. Area of bar = frequency

Question 7

What can cumulative frequency curves be used for

Answer 7

How many items fall below a particular value

Estimate medians, quartiles and percentiles

Question 8

What does the interquartile range equal

Answer 8

The upper quartile - lower quartile

Question 9

What is the cumulative frequency defined as

Answer 9

The number of data items less than or equal to that value

Question 10

How do you plot a cumulative frequency curve

Answer 10

x axis = upper limit

y axis = cumulative frequency