Thanks for the link.Hosam wrote: ↑Thu Nov 26, 2015 7:48 pm However, if you want to use Gpower you could get sample size of 138 respondent as the following (please correct me if I'm mistaken)
F tests  Linear multiple regression: Fixed model, R² increase
Analysis: A priori: Compute required sample size
Input: Effect size f² = 0.15
α err prob = 0.05
Power (1β err prob) = 0.95
Number of tested predictors = 5
Total number of predictors = 5
Output: Noncentrality parameter λ = 20.7000000
Critical F = 2.2828562
Numerator df = 5
Denominator df = 132
Total sample size = 138
Actual power = 0.9507643
Sample size calculation using G*power Analysis

 PLS Junior User
 Posts: 1
 Joined: Sat Oct 06, 2018 4:58 pm
 Real name and title: jedisummary
Re: Sample size calculation using G*power Analysis

 PLS Junior User
 Posts: 2
 Joined: Tue Dec 24, 2019 9:53 am
 Real name and title: Danu Rahardja Singgih
Re: Sample size calculation using G*power Analysis
can anyone show me a tutorial on how to use the program? i a currently doing my thesis, with 2 independent variable, 1 mediator and 1 dependent

 PLS Junior User
 Posts: 1
 Joined: Fri Feb 21, 2020 7:10 am
 Real name and title: astra tomy
 Contact:
Re: Sample size calculation using G*power Analysis
thanks for the help guys

 PLS Junior User
 Posts: 5
 Joined: Mon Mar 01, 2021 1:56 am
 Real name and title: chentianzhi student
Re: Sample size calculation using G*power Analysis
Hello all,
I have a reflectiveformative type model and there are two first order latent variables. I am interested in testing the weights of the two first order latent variables to second order latent variable. I will use the disjointed two stage approach to model analysis. Should I calculate the sample size in the second stage by using n=2 for the number of predictors and the ttest method? Or should I calculate the sample size in the first stage by using n=20 for the number of predictors and the ttest method? (one of the first order latent variables have 20 indicators and another have 9 indicators.)
Thank you.
I have a reflectiveformative type model and there are two first order latent variables. I am interested in testing the weights of the two first order latent variables to second order latent variable. I will use the disjointed two stage approach to model analysis. Should I calculate the sample size in the second stage by using n=2 for the number of predictors and the ttest method? Or should I calculate the sample size in the first stage by using n=20 for the number of predictors and the ttest method? (one of the first order latent variables have 20 indicators and another have 9 indicators.)
Thank you.

 PLS Junior User
 Posts: 6
 Joined: Thu Jul 09, 2020 1:36 pm
 Real name and title: Navya Jain , Research Scholar
Re: Sample size calculation using G*power Analysis
Hi everyone,
In continuation to the discussion here, I had a query.
When calculating minimum sample size in GPower for a study that has one tailed hypotheses, I have used the following settings (based on 2nd order, 2 latent variables predicting another 2nd order latent variable, all reflective):
ttest
Linear multiple regression: Fixed model , single regression coefficient
A priori analysis
One tailed
Effect size 0.05
Alpha error prob. 0.05
Power 0.80
No. of predictors = 2
This gives me a minimum sample size of 126
As part of my analysis, I have done a group specific analysis (2 groups with greater than 126 sample size) as well as analysis of the total dataset (greater than 300 sample size).
Am I correct to assume that I have followed the correct settings for GPower and I can say that the sample size of the study is sufficient based on the above GPower A priori analysis?
In continuation to the discussion here, I had a query.
When calculating minimum sample size in GPower for a study that has one tailed hypotheses, I have used the following settings (based on 2nd order, 2 latent variables predicting another 2nd order latent variable, all reflective):
ttest
Linear multiple regression: Fixed model , single regression coefficient
A priori analysis
One tailed
Effect size 0.05
Alpha error prob. 0.05
Power 0.80
No. of predictors = 2
This gives me a minimum sample size of 126
As part of my analysis, I have done a group specific analysis (2 groups with greater than 126 sample size) as well as analysis of the total dataset (greater than 300 sample size).
Am I correct to assume that I have followed the correct settings for GPower and I can say that the sample size of the study is sufficient based on the above GPower A priori analysis?