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I am using the NIST test suite to test random binary numbers. when I tried it for data.pi, the generated report has some items that can not be interpreted. for example, the coeffecients named C0~C10. I am using 20 bit streams. My question is how do these coefficients relate to the 20 streams? and what do they represent enter image description here

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C1 through C10 is a histogram of p values for the tests that you just ran. It represents the range of 0 <= p <= 1 partitioned into ten categories. So in the first line, you got two p values <= 0.1 and one in the range 0.1 <= p < 0.2.

We expect a uniform spread of them across the chart as a Kolmogorov–Smirnov uniformity test is then performed on them to achieve the final p value in the "P-VALUE" column.

That row adds up to 20 (your 20 streams), as in 20/20. But there's a quirk in that a failing p value (p < 0.01) is not counted as a pass (clearly), but still is histogrammed. That's why the next line adds up to 20 yet only 19 tests passed.

Hi and welcome :-)

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  • $\begingroup$ Thanks it was very clear $\endgroup$
    – O. Nawwar
    Aug 22, 2023 at 6:17

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