Representation Of Data

Question 1

Discrete data

Answer 1

Usually as a result of counting

Distinct numbers, colours

Question 2

Continuous data

Answer 2

Usually as a result of some measurement

Heights, weights

Question 3

How to find the lower, upper and median in a stem and lead graph

Answer 3

• median : the middle value or the average of the two middle values
• lower quartile: the median of the lower half
• upper quartile: the median of the upper half

Question 4

Histograms are used for what type of data?

Answer 4

Continuous data , and discrete data only when frequency is very large

Question 5

Frequency density

Answer 5

Frequency divided by class boundary interval width

Question 6

What to do if the interval is open ended

Answer 6

Close the interval to double the size of the most common interval

Question 7

Things to watch out for when completing histograms (graphs in general)

Answer 7

Title 
Even spread
Labelled y and x axis 
For histograms 
Watch out for class boundary adjustments
And there are no gaps between the bars

Question 8

Cumulative frequency graphs

Answer 8

Cumulative frequency means hat the frequency of the previous column is carried to the next.

|3|(3+5)8|

Also on the side opposite the y axis percentage must also be marked to calculate median lq and uq

Question 9

Median mode mean

Answer 9

• median : the middle data
• mode : the most frequent data value
• mean : average

Question 10

Mean for : individual discrete data

Discrete data with frequencies

Answer 10

Individual :
mean = sum of all individual data divided by the number of data

Frequency:
Mean = sum of the frequencies (total amount of data values) x sum of all values all divided by sum of the number of values

Question 11

Mean for grouped continuous and classified discrete data.
Example
Speed of cars grouped 30-x-35

Answer 11

Mean = sum of the( middle points times the frequency ) divided by the total number of data values.