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Given $P_k$, the truncated Prime $\zeta$ function, defined like $ P_k(it):=\sum_{n=1}^k p_n^{it}, $ where $p_n$ is the $n$th prime. What's the probability to find a value or range of $t$ less than $T$, where $|P_k(it)|<\epsilon$?

EDIT By that I mean, among all values of $t, how large is the portion of values, where $|P_k(it)|<\epsilon$?

To give an example, I plotted $P_{500}(it)$, where $0:

$\hskip0.7in$enter image description here

The lower plot shows the portion of values that lies below a certain threshold. Almost all values lie below $.1$. I interpret the lower plot as the sum over the distribution.

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    No idea. And no idea whether this is known by the experts.2012-11-15

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If $t$ is chosen randomly (uniformly) from a large enough interval, $p_n^{it}$ for different $n$ should be good approximations to independent random variables with uniform distribution on the unit circle. This distribution has mean $0$ and covariance matrix $\pmatrix{1/2 & 0\cr 0 & 1/2\cr}$. The sum, for large $k$, has approximately a bivariate normal distribution with mean $0$ and covariance $\pmatrix{k/2 & 0\cr 0 & k/2\cr}$. Its absolute value has PDF $f(r) = \dfrac{2 r}{k} e^{-r^2/k}$ for $r > 0$,
CDF $F(r) = 1 - e^{-r^2/k}$ for $r > 0$, mean $\sqrt{k\pi}/2$ and standard deviation $\sqrt{(1-\pi/4) k}$.

Are you sure your $P_k$ doesn't have a factor $1/k$?

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    it has, thanks...2014-03-09