# Tagged Questions

Beta regression is useful when the dependent variable is bounded, or when it has a ceiling or floor effect. It can also be used for modeling both the mean and the variance.

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### visualization of interaction effects: using predicted values?

I am currently working on a study in which I am using beta regression (in Stata). My depend variable is bounded between 0 and 1. To interpret the effects of my independent variables I am using the ...
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### Model multilevel proportion data

Suppose that one has data on a proportion $P$ measured on a continuous scale. Further suppose that this data has a grouped structure -- some proportions are clustered according to a certain variable ...
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### Model bounded proportion data in a repeated measures design

I'm modeling the amount of organic content in bird bones (a percentage) in two different conditions and also over two time periods. The design is repeated measures - observations in both conditions ...
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### Variance-covariance matrix of the errors in linear regression

How is the var/cov error matrix calculated by statistical analysis packages in practice? This idea is clear to me in theory. But not in practice. I mean, if I have a vector of random variables ...
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### Shares on total as dependent variable

I would like to ask for your help with the following issue. I am trying to estimate the model where dependent variable is a share of total (e.g. share of the US economy in terms of GDP on total world ...
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### Dealing with regression of unusually bounded response variable

I am attempting to model a response variable that is theoretically bounded between -225 and +225. The variable is the total score that subjects got when playing a game. Although theoretically it is ...
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### Beta regression of proportion data including 1 and 0

I am trying to produce a model for which I have a response variable which is a proportion between 0 and 1, this includes quite a few 0s and 1s but also many values in between. I am thinking about ...
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### How to interpret an insignificant main effect that became significant at the presence of interaction effects in moderated regression analysis? [duplicate]

Possible Duplicate: What if interaction wipes out my direct effects in regression? I did hierarchical regression analysis on my data due to having interaction effects in my research model. ...
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### How to interpret inconsistent Beta values in different steps of hierarchical regression analysis?

I did hierarchical regression analysis on my data due to having moderation effects in my research model. R2 increased from .695 in model1 (main effect only) to .734 in model2 (main &interaction ...
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### What's a time series model for forecasting a percentage bound by (0,1)?

This must come up---the forecasting of things that are stuck between 0 and 1. In my series, I suspect an auto-regression component, and also a mean-reverting component, so I want something that I can ...