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Sample Size Required to Achieve a Desired Confidence Level

(with proportion defective = 0.20)

p=0.20

Number of Failures

Confidence Levels

60%

80%

90%

95%

99%
0 4 8 11 17 22
1 10 16 19 24 32
2 16 21 27 30 40
3 21 28 33 38 49
4 27 34 39 45 56
5 32 39 46 50 63
6 37 45 51 58 70
7 42 50 58 64 77
8 47 56 64 70 84
9 52 62 69 77 90
10 58 67 76 82 97
11 63 73 81 89 104
12 68 78 87 95 109
13 73 84 93 100 117
14 78 89 98 107 122
15 83 95 104 112 129
16 88 100 110 118 136
17 94 106 116 124 140
18 99 111 121 130 148
19 104 117 126 136 154
20 109 122 133 141 160
22 119 133 144 153 172
24 129 144 155 165 184
26 139 154 166 176 196
28 150 165 177 188 209
30 160 176 188 199 220
35 186 202 216 227 250
40 211 229 241 255 278
45 236 255 270 283

308
50 262 281 297 310

336

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