# Information about parameters using priors distributions [duplicate]

When using the "non-informative" prior $$\pi(\mu,\sigma)\propto\frac{1}{\sigma^2}$$ where $$\pi(\mu)\propto1$$ and $$\pi(\sigma^2)\propto\frac{1}{\sigma^2}$$

Where is the no information for the parameter?

and if would be informative prior, Where one would see the 'information' given?

I saw the definition on Wikipedia https://en.wikipedia.org/wiki/Prior_probability and there mentions 'An informative prior expresses specific, definite $$\color{blue}{\text{information}}$$ about a variable.'

My question is where is this $$\color{blue}{\text{information}}$$ given in my particular example for instance?

Could you help please?

## marked as duplicate by kjetil b halvorsen, Michael Chernick, Xi'an bayesian StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Feb 11 at 6:09

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• I don't think this question is a duplicate. The proposed duplicate is asking about the rationale for using informative vs. uninformative priors, whereas this question seems to be asking about how to identify informative vs. uninformative priors. – user20160 Feb 11 at 0:02
• @user20160 I don't think this is a duplicate neither. Though I didn't mean to ask how to identify informative vs. uninformative priors. I meant the current questions actually :) . I saw the definitions on Wikipedia en.wikipedia.org/wiki/Prior_probability and there mentions An informative prior expresses specific, definite information about a variable. where is this information given? – Isa Feb 11 at 1:17
• @user20160 Your question 'how to identify informative vs. uninformative priors' is an interesting one btw. – Isa Feb 11 at 1:20
• @Isa I see. You might consider editing your question to include this. This could help clear up the duplicate issue, and help people understand exactly what you're asking. – user20160 Feb 11 at 1:42
• @user20160 I've edited – Isa Feb 11 at 2:03