Hi all 
i need help in one silly question
Can any one help me understand the meaning of p value?
if we say **p value = 0.05** then what does that means.
what is confidence interval?
If we say **95% confidence** interval then what does that means.

I read certain article where it says p value is error estimation . If we are dealing with **trancriptome data** then in this data what could  be error. meaning people select **pvalue < 0.05 as significance** what this significance means???

Thanks ..
When running a test you are running a risk of type I error (accepting null hypothesis when it is not true, false positives, alpha) and type II error (failing to reject the null hypothesis when in fact it is false, false negatives, beta). P value is the smallest probability (alpha) at which your test is still significant. P-value of 0.05 basically means you are running a  5% risk that your test will be significant by chance and this value is commonly accepted as sufficient for a single test. So when running a test and returning the P-value of e.g. 0.003 (which is smaller than 0.05) you accept the value as significant since the probability of running a type I error (false positives, basically your P value) is smaller than prior selected (0.05). 

Confidence intervals give you a range of values that would be significant at a preselected confidence level (1 - selected P value * 100 --> 1 - 0.05 * 100 = 95%). 