Basic Summary Stats and Data Visualisation

Question 1

What types of data are there?

Answer 1

There is both discrete and continous data. Discrete data can be broken up into categorical (no order) or ordinal (there exists and explicit order)

Question 2

What decriptive stats exist?

Answer 2

• Max
• Min
• Average
• Frequency
• Variance
• Standard deviation

Question 3

What are examples of central tendency measures?

Answer 3

• Mean
• Mode
• Median

Question 4

What are examples of measures of spread?

Answer 4

• Range
• Variance
• Standard deviation
• Quartiles/Percentiles

Question 5

What five numbers are needed for a box plot?

Answer 5

• Median: The middle value
• Q1: The middle value below the median
• Q3: The middle value abover the median
• Minimum: The lowest value
• Maximum: The highest value

Question 6

Whats an important measure of spread in a boxplot?

Answer 6

IQR = Q3 - Q1

Question 7

What is an outlier?

Answer 7

An outlier is a data object that deviates from the normal objects as if it were generated by a different mechanism

Question 8

What makes a Tukey boxplot different to a normal boxplot?

Answer 8

• Max value is the maximum within 1.5 IQR’s of Q3
• Min value is the minimum within 1.5 IQR’s of Q1
• Suspected outliers are denoted by a black outlined circle and are > 1.5 IQR’s above Q3 or below Q1
• Outliers are denoted by a filled in black circle and are >3 IQR’s above Q3 and below Q1

Question 9

What is a histogram?

Answer 9

• A data visualisation that counts the frequency of a certain number of points.
• Points are grouped together in bins that can be of the same size (common) or of varied size.
• The x-axis has the bins and the y-axis has the relative frequencies

Question 10

What is a bar plot?

Answer 10

• A data visualisation that has shows for categorical variables some numeric quantity associated with it
• The x-axis is the categorical variable and the y-axis has the relative frequency

Question 11

What is a scatter plot?

Answer 11

• A data visualisation that shows the relation between two numeric variables
• The x-axis and y-axis both represent numeric varaibales

Question 12

What are elements of good visualisations?

Answer 12

• Meaningful titles
• Labeled axes
• Its suitable for the data set
• Can be interpreted on it’s own
• Has no redundant infomation