PPT11 Introduction to Time Series

# PPT11 Introduction to Time Series - McGill University...

This preview shows pages 1–12. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Fall’09 Introduction to Time Series Read: Business Statistics (A Second Course) , Custom Edition for McGill University Chapter 9
A time series is a collection of data obtained by observing a response variable at periodic points in time. If repeated observations on a variable produce a time series, the variable is called a time series variable . y t is used to denote the value of the variable at time t Time Series Data

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Longitudinal Studies (Time Series). .. The study of the evolution of a process over time It consists of: 1. Collecting measurements over time 2. Comparison of measurements from different time periods 3. Documentation of variation over time 4. Evaluation of change
A Time Series Can Consist of Four Components: Trend (T) or Secular A long-term, relatively smooth pattern or direction demonstrated by the data Cyclical (C) A wavelike pattern exhibiting a long-term trend that is generally seen over a number of years Seasonal (S) A pattern that occurs over short repetitive calendar periods Random or Residual (R) The irregular changes in the time series that are not caused by any other component. It can hide the existence of other components

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Time Series Models Time series is usually expressed as an additive or multiplicative model. That is, y t = T t + C t + S t + R t or y t = T t × C t × S t × R t Trend Cyclical Seasonal Random
Overview of Time Series Models

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Time Series Plots in Minitab
Time Series Plots: Example 1: SALES35 data Retail sales in $1000 for Retail sales in$1000 for a Sporting Goods store. a Sporting Goods store.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Example 2: Gasoline Sales (in 1000 litres) Time Period Year Quarters Sales 1 1 1 39 2 2 37 3 3 61 4 4 58 5 2 1 18 6 2 56 7 3 82 8 4 27 9 3 1 41 10 2 69 11 3 49 12 4 66 13 4 1 54 14 2 42 15 3 90 16 4 66
Sequence (Time Series) Plot of Gas Sales 0 10 20 30 40 50 60 70 80 90 100 0 2 4 6 8 10 12 14 16 18 Sales (10 litres) Time Gasoline Sales

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 39

PPT11 Introduction to Time Series - McGill University...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online