Model Fitting and Assessing Fit Quiz

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What does a non-significant Chi-square statistic indicate about the model fit?

The model fits well

How can the significance of a parameter in a model be tested?

By fixing it to zero

What happens when a parameter is dropped from a model?

The model may get significantly worse

What does it mean if a parameter is considered non-significant in terms of model fit?

It does not add much to the model Signup and view all the answers

What does a Chi-square value of 5.18 with 1 degree of freedom indicate?

The parameter is significant Signup and view all the answers

What is the general statistical power to detect effects of C?

Very low Signup and view all the answers

What is the formula to calculate heritability (h2 or a2) using Falconer's rules?

(rMZ - rDZ) * 2 Signup and view all the answers

What does the shared environment component (c2) represent in Falconer's rules?

Shared environment component represents the difference between the monozygotic correlation and heritability component. Signup and view all the answers

How is the non-shared environment component (e2) calculated in Falconer's rules?

e2 = 1 - rMZ Signup and view all the answers

What are the steps involved in Estimation with Structural Equation Modelling (SEM)?

<ol> <li>Put together a theoretical model with path tracing, 2. Derive predictions from the model, 3. Compare predictions to observed relationships, 4. Use fit functions to assess, 5. Conclude the plausibility of the model if it fits well.</li> </ol> Signup and view all the answers

Explain the principle of having a maximum of one curved arrow per path in the context of modeling.

The principle limits the complexity of the model by allowing only one curved arrow per path, which helps in maintaining model simplicity and interpretability. Signup and view all the answers

Why is the double-headed arrow from the independent variable to itself included in modeling?

The double-headed arrow is included to represent the latent variable's variance, even if there are other double-headed arrows in the chain. Signup and view all the answers

What is the required sample size to detect a heritability of 60% with 80% power and a c2 of 10%?

62 MZ and DZ pairs Signup and view all the answers

Why does detecting a c2 of 10% with a h2 of 60% require a larger sample size compared to detecting heritability?

To detect c2 of 10% with a h2 of 60%, 2200 MZ and DZ pairs are needed. Signup and view all the answers

What is the problem faced in twin studies when the sample size is too small to detect a certain proportion of C?

The AE model is selected as the best model, inflating the heritability estimate. Signup and view all the answers

What happens to familial effects when the C component is dropped from the model?

All familial effects will be attributed to A, resulting in a very high heritability estimate (>70%). Signup and view all the answers

Why is it important to report the full ACE model along with the 95% CI in data analysis?

To provide a fair representation of the data and avoid bias in parameter estimates. Signup and view all the answers

Model Fitting and Assessing Fit Quiz

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