P value

value /val·ue/ (val´u) a measure of worth or efficiency or of the activity, concentration, etc., of something.

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normal values  the range in concentration of specific substances found in normal healthy tissues, secretions, etc.

P value , p value the probability of obtaining by chance a result at least as extreme as that observed, even when the null hypothesis is true and no real difference exists; if it is ≤ 0.05 the sample results are usually deemed statistically significant and the null hypothesis rejected.

reference values  a set of values of a quantity measured in the clinical laboratory that characterize a specified population in a defined state of health.

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P value,

(in research) the statistical probability of the occurrence of a given finding by chance alone in comparison with the known distribution of possible findings, considering the kinds of data, the technique of analysis, and the number of observations. The P value may be noted as a decimal: P <.01 means that the likelihood that the phenomena tested occurred by chance alone is less than 1%. The lower the P value, the less likely the finding would occur by chance alone.

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significance 

In statistics, an indication that the results of an investigation on a population (e.g. patients) differ from those of another population (e.g. general) by an amount that could not happen by chance alone. This is evaluated by establishing a significance level, that is the probability, called p value, which leads us to reject or accept the null hypothesis H_o (there is no significant difference between two populations and the difference is attributed to chance) and accept or reject the alternative hypothesis H₁ that there is a statistically significant difference between two populations. A p value p < 0.05 is often considered significant, but the lower this figure, the stronger the evidence. See randomized controlled trial.