Strike-Out-Not-Out

Sometimes, you can see batters swing and miss after two strikes, but runs to first base. As everybody knows, swinging and missing after two strikes is strike out because swinging counts as strike. However, there are special occasions when batters are allowed to go to first base to get safe. When batter swings and misses and catcher also misses and doesn't catch the ball, batter can attempt to run to first base while catcher runs to get baseball and throw it to first base. If batter touches the first base before any fielder catch the ball, the batter is safe. The batter is out if the ball reaches the first base first.
If batter is safe in first base, batter becomes a runner, but out count number doesn't go up. However, if the batter gets out, one out count is added.
After two outs, batter can run after getting strike out not out, regardless of having runner on 1st base or not. However, if the out count is zero or 1 and there is runner on 1st base, strike out not out doesn't work.
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OPS

OPS stands for on-base plus slugging and is calculated by on-base + slugging average. Having over 1.000 OPS means really good at batting. Like SLG and OBP, it doesn't have a big meaning, but serve as data to compare how good the batter is.
Just like SLG and OBP, batters usually have high numbers in the beginning of season, but usually goes down at the end of season compared to the beginning. It is because all the fielders, also the batters, get tired because stamina goes down when playing in the sun.

SLG

SLG is slugging percentage and is used to measure if a hitter is whether focusing on contact or power. The equation for SLG is (1 x number of a base hit) + (2 x number of two base hit) + (3 x number of three base hit) + (4 x number of home-run) all added divided by total number of at bat. For example, in total of 20 bats, you hit three of single base hits, two of two base hits, 1 of three base hit, and 1 home-run, the equation would be (3 + 6 + 3 + 4) / 20. Therefore, SLG would be .800.
The highest possible SLG is 4.000. However, it is almost impossible to have because, in order to have 4.000 SLG, you have to hit home-runs every time at bat.

OBP

OBP is abbreviation for 'on base percentage.' The equation for OBP is (number of hits + number of base on balls + number of hit by pitch ball) divided by (number of at bat + number of base on balls + number of hit by pitch ball + number of sacrifice fly). OBP always have to be higher than hit average.
OBP is used to evaluate how well a batter can distinguish strikes and balls. Normally, if OBP is higher than 0.400, then the hitter has very OBP. In other words, better hitter has high OBP.