Not a great night
Tsurenko retired.
Jakupovic lost the plot in the first set after the first 5 games where she was very competitive and had game points in each of the first 5 games including 5 break points but ended up being down 2-3 After that it was a stream of UFE's until late in the 2nd set where she had 2 BP's to level at 5-5 but couldn't convert. Too little too late.
The only bright spot was Stosur.
So record now
52-41
+316 +2.5% ROI
My head is slightly above the water.....
After the unexpected results last night I've been crunching a few numbers.
So far on grass I have gone 23-25 for -$584 -10.2% ROI c/w 26-19 for $901 +13.4% on clay.
I would need a sample size of around of 230 matches on each surface to be 85% confident that these were actually different using parametric stats.
As the sample sizes we usually work with in sports betting are low I've tried the analysis using non-parametric stats, which are not as powerful but can be useful for smaller samples sizes. These indicate that I can be a little confident that these results are not due to chance even with the small sample sizes.
I've looked at the Kvitova, Stosur, Svitolina, Garcia and Maria matches to see if I can learn anything from the numbers. And hopefully be able to improve my grass results before I go broke. It looks like grass is a more volatile surface and difficult for players to maintain consistent levels of performance.
My take on the matches just from looking at the numbers, doesn't give the whole story.
Stosur and Maria seem to have made significant improvement's/adjustments to their game at least on grass.
Maria has played statistically better in her last 2 matches by around the same amount each time, the odds makers have adjusted their model to take this into account when setting their new lines. Similar with Stosur.
I don't think they adjusted enough and the bettors seem to think they have over adjusted. Stosur and Maria should both be live dogs for tonight's semi-finals at value odds.
Kvitova and Kenin both had slightly better performances combined with slightly poorer performances than their opponents.
Kvitova served a bit better and Goerges served a bit worse than normal, as both rely heavily on their service games this ended up having a big effect on the outcome.
Similar with Garcia, Garcia struggled a little with her serve and Kenin's serve was going pretty good, end of story.
So a small drop off in performance from one player and a small increase in performance from the other can have a big impact on the outcome of the match.
The Buza match is difficult to explain, the gap between expected and actual performance was huge. I didn't see the match but I would guess that Svito had some sort of injury or was unwell in some way. The result was what you would expect when Halep plays a 200 ranked player.
When Svito got beaten by Halep she got 47% of the points, but only managed to get 41% against Buza........
I'll post my picks a bit later on.