What are the critical values that define the 80^th percentile for HC, 75^th percentile for CO, and 90^th percentile for NOX? Show your work on the worksheet without using the built-in functions for quantiles. values are:

HC	CO	NOX
0.34	3.95	1.38
0.36	2.03	1.80
0.37	4.12	1.20
0.38	4.10	1.47
0.38	5.21	1.24
0.39	7.24	1.45
0.41	4.42	1.31
0.41	4.95	1.16
0.41	3.38	1.33
0.41	1.85	2.27
0.41	2.26	1.87
0.43	3.81	1.79
0.44	7.51	1.08
0.46	8.60	1.17
0.46	3.99	2.01
0.47	4.74	1.83
0.47	5.22	1.12
0.48	3.45	2.20
0.48	4.62	1.47
0.50	5.01	1.28
0.50	12.10	1.44
0.51	4.10	1.78
0.51	5.69	1.73
0.51	5.79	1.51
0.52	4.29	2.94
0.52	6.35	1.45
0.52	6.78	1.15
0.55	12.30	1.22
0.55	7.47	1.39
0.56	5.36	1.26
0.57	5.04	1.49
0.57	6.02	1.31
0.58	6.02	0.97
0.60	9.62	0.71
0.61	8.43	1.06
0.64	7.98	1.32
0.65	14.67	0.21
0.65	11.20	0.95
0.70	22.92	0.57
0.70	14.83	1.16
0.72	14.59	0.60
0.73	14.97	0.51
0.83	11.53	1.32
0.83	15.13	0.49
0.87	19.00	0.78
1.02	23.53	0.86