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manual:diagram_based_power_analysis

# Conduct Monte Carlo based power analysis using the path diagram interface

Once can conduct power analysis using Monte Carlo based method by drawing a path diagram with population parameters. An example is given in the figure below:

## Rules to specify the population parameters

• A number such as 1, 0.5, and -2, on the path will be used as population parameters to generate data from the model and the path will be estimated as free parameters in Monte Carlo simulation.
• To fix a path in the estimation, use @. For example, @1 will be fixed at 1.
• A path can be provided a name.
• For example, a?0.5 means the parameter values is 0.5, the parameter name is a, and the path needs to be estimated.
• a@0.5 means the parameter values is 0.5, the parameter name is a, and the path will be fixed at 0.5 when estimating the model.
• To specify the skewness and kurtosis for an observed variables, using the path from to . Two numbers separated by “;” are used with first one denoting the skewness and the second one denoting the kurtosis.
• Default parameters
• By default, the unspecified variances will be given the value 1 and the unspecified covariance will be given the value 0.
• The unspecified regression/loading paths will be given a value 0.
• The unspecified mean/intercept will be givens a value 0.

## Conduct the power analysis

### Required input

• Sample size: an integer number for sample size
• Significance level: 0.05 typically
• MC replications: How many Monte Carlo replications are used to estimate power. 1000 typically.
• Power parameters: Parameters other than specified in the diagram. For example, one can get the power for an indirect effect a*b. To get it, specify ab := a*b. Notice that “:=” is used to define a new parameter. Each line provides one such parameter.
• Notes: put a note for the analysis.

### Required input

manual/diagram_based_power_analysis.txt · Last modified: 2015/04/28 13:38 by 10.45.84.252

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