Are My Stats All Screwed Up?

[JFB37]

I try to keep detailed records of my live play stats but there is something going on that I don't understand. I keep the stats in terms of "pokertracker big bets" per hour (i.e., 2x the big blind).

Here are my stats for the last ten sessions:

<font class="small">Code:</font><hr /><pre>Session Win Rate Cumm Win Rate Cumm Win Rate Confidence Interval
6.57 5.31 0.38
8.05 5.33 0.31
(37.50) 4.92 0.28
33.32 5.26 0.34
55.00 5.84 0.37
11.30 5.90 0.34
10.76 5.97 0.45
55.67 6.43 0.36
44.44 6.69 0.33
(50.74) 5.54 0.45</pre><hr />

This looks very strange to me. Look at the last five entries, for example. The confidence interval takes a big jump after a small win, declines after a couple of big wins and then takes another big jump after a big loss. Does that pattern make sense?

I have hunted around in my spreadsheet for an error in my formulas and not found one. The point of the post is whether, based on these numbers, others agree that this looks wrong and believe that I should keep looking.

Thank you for any assistance.