How do Atheletes in Track and Field Get into the Olympics

I have often wondered HOW they decide who is invited to the Olympics.  Turns out it isn't completely complicated.  There are 2 qualifying times, "A" time and "B" time, and the International Athletics Federation tracks people's time different certified meets.  Of course, in case with throws it "distance" not "time", but generally you get the idea.
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You (as Country X) can send up to 1, 2 or 3 athletes if they all meet the "A" time. If none of Country X's athletes meet the "A:" time, but a few meet the "B" time, you may send any one (1) of those athletes that meets the "B" time.  If you are a country that has no athletes that meet either time, you can send a single athlete in each event.
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If you want to know what the A and B bars are set at, here they are (from Wikipedia):

Men's Events			Women's Events
Event	Men's A	Men's B	Event	Women's A	Women's B
Men's 100 metres	10.18	10.24	Women's 100 metres	11.29	11.38
Men's 200 metres	20.55	20.65	Women's 200 metres	23.10	23.30
Men's 400 metres	45.30	45.90	Women's 400 metres	51.55	52.35
Men's 800 metres	1:45.60	1:46.30	Women's 800 metres	1:59.90	2:01.30
Men's 1500 metres	3:35.50	3:38.00	Women's 1500 metres	4:06.00	4:08.90
Men's 5000 metres	13:20.00	13:27.00	Women's 5000 metres	15:20.00	15:30.00
Men's 10,000 metres	27:45.00	28:05.00	Women's 10,000 metres	31:45.00	32:10.00
Men's Marathon	2:15:00	2:18:00	Women's Marathon	2:37:00	2:43:00
Men's 3000 Steeplechase	8:23.10	8:32.00	Women's 3000 Steeplechase	9:43.00	9:48.00
Men's 110 metres Hurdles	13.52	13.60	Women's 100 metres Hurdles	12.96	13.15
Men's 400 metres Hurdles	49.50	49.80	Women's 400 metres Hurdles	55.50	56.65
Men's High Jump	2.31	2.28	Women's High Jump	1.95	1.92
Men's Pole Vault	5.72	5.60	Women's Pole Vault	4.50	4.40
Men's Long Jump	8.20	8.10	Women's Long Jump	6.75	6.65
Men's Triple Jump	17.20	16.85	Women's Triple Jump	14.30	14.10
Men's Shot Put	20.50	20.00	Women's Shot Put	18.30	17.20
Men's Discus Throw	65.00	63.00	Women's Discus Throw	62.00	59.50
Men's Hammer Throw	78.00	74.00	Women's Hammer Throw	71.50	69.00
Men's Javelin Throw	82.00	79.50	Women's Javelin Throw	61.00	59.00
Men's Decathlon	8200	7950	Women's Heptathlon	6150	5950
Men's 20 kilometres walk	1:22:30	1:24:30	Women's 20 kilometres walk	1:33:30	1:38:00
Men's 50 kilometres walk	3:59:00	4:09:00	-	-	-
Men's 4x100 metres relay	Top 16 Teams		Women's 4x100 metres relay	Top 16 Teams
Men's 4x400 metres relay	Top 16 Teams		Women's 4x400 metres relay	Top 16 Teams