Collecting Data

Question 1

Categorical and numerical

Answer 1

Categorical is data not use number , numerical is data with numbers with value

Numbers can be categorical like numbered items

Question 2

Why is a stem and leaf diagram good for grouping data

Answer 2

It groups data making it easier to see and interpret trends such as MEDIAN, QUARTILES

• length of lines gives shape of each distribution
• but also DOESNT LOSE RAW DATA, EVERYTHING IS KEPT THERE
• can also allow for two sets of data to be compared side by side whilst still grouped

Question 3

Pie chart vs bar chart

Answer 3

Used for categorical data

• pie chart compares proportions and obscures frequencies ,
• but scales down to 360° which is useful for comparing another Side buy Side
• bar chart shows frequencies

Question 4

Vertical line graphs

Answer 4

Show discrete data

Doesn’t confuse reader to do with width being connected to data , thus a straight line just shows data

Question 5

Dot plot

Answer 5

Again makes it easier to see group of data

You can make a Key too

Question 6

Histogram/ why not use frequency diagram

Answer 6

Continuous data 
- frequency diagrams show a distorted version of data when class intervals are different  which may show data being skewed , histogram uses area to avoid this

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Question 7

Skewed data

Answer 7

Positively skewed means less on the right , lower values meaning it is skewed to the right so positive

Negative means skewed to the left (less values on left, more are on higher ) so negatively skewed

Symmetrical is symmetrical