If one transforms sample data of prime gaps by $g_n := (-1)^n (p_{n+1} - p_n)$ then tests the means of positive and negative gaps one finds the mean difference between groups to be 0. Taking the mean value of the gaps $\mu_n$ to give $p_n + \mu_n$ one can derive a +-$1.96\sigma_n$ confidence interval, assuing normal distribution, such that $p_{n+1}\in I$ for arbitrarily large n. Here are my results using 3000 gaps:
Welch Two Sample t-test
data: positivegaps and negativegaps t = 74.083, df = 2999, p-value < 2.2e-16 alternative hypothesis: true difference in means is not equal to 0 95 percent confidence interval: 17.82724 18.79656 sample estimates: mean of x mean of y 9.148568 -9.163333
My question is - why do the prime gaps seemingly sum to zero when transformed this way?