STATS Lec (1)- intro and data types

Question 1

Introduction to data

Answer 1

• Variable: Something that varies, having a range of possible values
  
  • Often a measurement or category e.g. height, eye colour, IQ score
• DATA: a series of observations, measurements or facts: information that can be analysed
• DATA analysis: is a process of gathering, modelling and transforming data with the goal of highlighting useful information, suggesting conclusions and supporting decision making

Question 2

Scales of measurement

Answer 2

• Variables differ from one another in terms of their underlying properties, they can be
• Nominal (categorical)
• Ordinal (Categorical, Rank or Order)
• Interval (true increments, but no real 0 point)
• Ratio (true increments including 0)

Question 3

Nominal (categorical data)

Answer 3

• Data are not numerical
• Items are just named or put into categories
• Physical Attributes: sully is fury; mike is not furry
• e.g. gender, colour,

Question 4

Ordinal data

Answer 4

• Data can be organised into ranks
• Variables ranked and scored on a fixed scale
• Intervales between ranks are not equal
• E.g. small, medium and large chips, abundance fungi in soil sample 0 (none) to 5 (abundant), pain scores

Question 5

Interval data

Answer 5

• Data on fixed scales which contain equal intervals
• No true zero (there is no nothing temperature)
• e.g. temperature, shoe size
• Sully = size 8 feet
• Mike = size 4 feet

Question 6

Ratio data (continuous)

Answer 6

• Highest level of data
• True zero point
• e.g. height, distance
• Sully = 8ft
• Mike = 4ft

Question 7

Measurement scale

Answer 7

• Remember the data levels lie on a continuum with ratio data as the highest level
  
  • Data which is ratio can also be all other levels)
• Height as an examples
  
  • Nominal: sully is tall, Mike is small
  • Ordinal: sully is tallest, Mike is smallest
  • Interval: Sully is 4ft taller than Mike
  • Ratio: Sully is twice as tall as Mike

Question 8

Manipulation of data

Answer 8

• Nominal and ordinal data
  
  • Data is in categories
  • There is no mathematical relationship between the categories
• Interval and ratio
  
  • The relationship between data points can be mathematically defined
  • THEREFORE this data can be manipulated mathematically

Question 9

Test yourself what type of data

Colour of each car passing

Answer 9

• Nominal data

Question 10

Test yourself what type of data

Speed of each car passing through the junction

Answer 10

• Interval data

Question 11

Test yourself what type of data

Relative speed of successive cars

Answer 11

• Ratio data

Question 12

Test yourself what type of data

Number of tyres on the car

Answer 12

• Ordinal data

Question 13

Test yourself what type of data

Number of people in each car

Question 14

Test yourself what type of data

Gender of drivers

Answer 14

• Nominal