qualitative and forecasring analysis_15407051

qualitative and forecasring analysis
DIANA ADRIYANA (15407051)
qualitative analysis

Definitions
•Qualitative data
–Data in the form of text and pictures, not numbers
•Qualitative analysis
–Analysis of qualitative data in order to discover trends, patterns, and generalizations
•Grounded theory
–Theory formed bottom-up from the (usually qualitative) data
•Rich data
–Includes a lot of explanatory and context information

Why Qualitative Methods?
•Problem: Difficult to answer complex SE questions with a purely quantitative approach because
–Working with human subjects
–Typically have small sample sizes
–Experiments are expensive to run
–Need some support for a hypothesis before investing effort in full experiment
–Difficult to understand context variables
•Solution: Use a combination of quantitative and qualitative methods

Types of Results
A Qualitative Studywill result in:
–Propositions tied to a trail of “evidence”
–Well-grounded hypotheses
–Complex findings that incorporate the messiness of the phenomenon under study
–Explanations
–Areas for future study

When to Use
•Studying human behavior
•Lack of concrete hypotheses
•Variables hard to define or quantify
•Little previous work
•Quantitative results hard to interpret


for a better understanding, click this website.
www.cs.umd.edu/class/spring2006/cmsc735/slides/CMSC735%2011b%20Qualitative%20Analysis.pdf

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DIANA ADRIYANA (15407051)
forecasting method

Main idea of the trend analysis forecasting method
•Main idea of the method: a forecast is calculated by inserting a time value into the regression equation. The regression equation is determined from the time-serieas data using the “least squares method”

Main idea of the trend analysis method
Trend analysis uses a technique called least squares to fit a trend line to a set of time series data and then project the line into the future for a forecast.
Trend analysis is a special case of regression analysis where the dependent variable is the variable to be forecasted and the independent variable is time.
While moving average model limits the forecast to one period in the future, trend analysis is a technique for making forecasts further than one period into the future.

Evaluation of the trend analysis forecasting method
Advantages: Simple to use (if using appropriate software)
Disadvantages: 1) not always applicable for the long-term time series (because there exist several ternds in such cases); 2) not applicable for seasonal and cyclic datta patterns.

for a better understanding, click this website.
www.kf.vu.lt/~albud/progn/Erasmus/Engl-VU/ppt/trend_analysis.ppt