# blinreg function in R

Hello,

I am trying to use blinreg function in R but I haven't got papers and videos about it. The R-documentation is not even clear; it doesn't have worked examples.
I have got a continuous response variable with two explanatory variables (one continuous and one categorical). Using a uniform prior on the regression parameters (b0, b1, b2), I want to use blinreg to simulate an MC sample of 1000 draws from the joint posterior distribution of (beta, sigmasquare) and then to estimate the summary statistics.

Regards

Hi @teketo! Welcome!

The `LearnBayes` package (where `blinreg()` is found) is the companion package to the book Bayesian Computation with R by Jim Albert. The book website links to resources that might help you, including:

In case youâ€™re asking this question in connection with work for a class of some sort, please do be aware of our Homework Policy. If youâ€™re looking for more specific help with a problem in your code, the best place to start is by reading our FAQ: Tips for writing R-related questions.

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Thank you for the details.

I haven't got clearly examples on how to specify the priors in blinreg; the examples I have got used non-informative priors.
I just want how informative priors be used in blinreg with examples, which I couldn't find any.
Moreover, can I get clear idea about the design matrix - x?

Thanks

The documentation for `blinreg()` says that it:

Gives a simulated sample from the joint posterior distribution of the regression vector and the error standard deviation for a linear regression model with a noninformative or g prior.

Iâ€™m not sure if a g prior is what you mean by â€śinformative priorâ€ť? If so, then the information you want is in this part of the docs for `blinreg()`:

##### Usage
``````blinreg(y,X,m,prior=NULL)
``````
##### Arguments
`y` vector of responses
`X` design matrix
`m` number of simulations desired
`prior` list with components `c0` and `beta0` of Zellner's g prior

Reading this sort of documentation takes some getting used to, and this is a particularly terse example. That may be because this is a book companion package, and itâ€™s assumed you will be reading the book where more explanation may be offered (I donâ€™t know, I donâ€™t have a copy of that book at hand).

But putting together the two sections above, we can see that the default for the `prior` parameter is `NULL`. This is why in basic examples, you donâ€™t even see the `prior` parameter used â€” if a parameter has a default, you donâ€™t have to specify it when calling the function unless you want something different from the default.

By inference (hereâ€™s where the docs could be clearer!), `prior = NULL` corresponds to an uninformative prior. To call `blinreg()` with a g prior, we need to follow the instructions above and provide a list with certain named components as the `prior` parameter, like:
`prior = list(c0 =`Â `, beta0 =`Â `)`
with your desired values or calculations in the blanks.

Iâ€™m afraid I donâ€™t quite know what youâ€™re looking for here. Can you describe what youâ€™re confused about in more detail, or give a small example?