Introduction to Basic Statistics

1
Introduction to Basic Statistics

• Course SRT 3
• Teacher Mr. Evans

2
Your data

• What type of data did you collect?

3
Measures of Central Tendency

• Mean
• Median
• Mode

4
Measures of Spread

• Variance
• Standard deviation

5
Practice

• Find mean, Q1, Q2, Q3, s2, and s.
• 9.4, 8.7, 8.8, 11.5, 10.0, 9.7, 10.8, 9.5, 9.8,
  7.8, 10.5, 10.2, 10.9, 9.8, 8.9, 11.1

6
Outliers

• The first step in detecting outliers is visually.

7
Outliers Univariate

• Method 1 Standard Deviation
• More then ?2 standard deviation from the mean

8
Outliers Univariate

• Method 2 Quartiles
• Mild outliers
• Outside of (Q1 1.5 IQR, Q3 1.5 IQR)
• You learned this method in FST
• Extreme outliers
• Outside of (Q1 3 IQR, Q3 3 IQR)

9
Outliers So What?

• Outliers should always be identified and
  discussed.
• They should never be ignored.
• In scientific research, full disclosure is
  mandatory.
• You are not allowed to delete outliers
  automatically, without disclosure.

10
Outlier Practice

• Identify potential outliers by all methods.
• 9.4, 8.7, 8.8, 11.5, 10.0, 9.7, 10.8, 9.5, 9.8,
  7.8, 10.5, 10.2, 10.9, 9.8, 8.9, 11.1

11
Regression

• Fitting data to a model
• How do we measure how good the model is?
• Coefficient of determination (R2)

12
Practice

• Find the model that best fits this data.
• Give the R2 value.

13
Visualization