The scores for a certain test of intelligence are normallydistributed with mean 100 and standard deviation Find the 80thpercentile of these scores.
Below is the table used, I still cant figure out what the 80%would be here:
Standard Scores and Percentiles
?z-score
Percentile
?z-score
Percentile
?z-score
Percentile
?z-score
Percentile
minus?3.5
00.02
minus?1.00
15.87
0.00
50.00
1.1
86.43
minus?3.0
00.13
minus?0.95
17.11
0.05
51.99
1.2
88.49
minus?2.9
00.19
minus?0.90
18.41
0.10
53.98
1.3
90.32
minus?2.8
00.26
minus?0.85
19.77
0.15
55.96
1.4
91.92
minus?2.7
00.35
minus?0.80
21.19
0.20
57.93
1.5
93.32
minus?2.6
00.47
minus?0.75
22.66
0.25
59.87
1.6
94.52
minus?2.5
00.62
minus?0.70
24.20
0.30
61.79
1.7
95.54
minus?2.4
00.82
minus?0.65
25.78
0.35
63.68
1.8
96.41
minus?2.3
01.07
minus?0.60
27.43
0.40
65.54
1.9
97.13
minus?2.2
01.39
minus?0.55
29.12
0.45
67.36
2.0
97.72
minus?2.1
01.79
minus?0.50
30.85
0.50
69.15
2.1
98.21
minus?2.0
02.28
minus?0.45
32.64
0.55
70.88
2.2
98.61
minus?1.9
02.87
minus?0.40
34.46
0.60
72.57
2.3
98.93
minus?1.8
03.59
minus?0.35
36.32
0.65
74.22
2.4
99.18
minus?1.7
04.46
minus?0.30
38.21
0.70
75.80
2.5
99.38
minus?1.6
05.48
minus?0.25
40.13
0.75
77.34
2.6
99.53
minus?1.5
06.68
minus?0.20
42.07
0.80
78.81
2.7
99.65
minus?1.4
08.08
minus?0.15
44.04
0.85
80.23
2.8
99.74
minus?1.3
09.68
minus?0.10
46.02
0.90
81.59
2.9
99.81
minus?1.2
11.51
minus?0.05
48.01
0.95
82.89
3.0
99.87
minus?1.1
13.57
minus?0.00
50.00
1.00
84.13
3.5
99.98
