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Volume 20, Issue 5
An introduction to power and sample size estimation
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This article has corrections. Please see:
Correction - January 01, 2004
Correction: An introduction to power and sample size estimation - October 01, 2023
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An introduction to power and sample size estimation
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Online download statistics by month: September 2003 to October 2024
Abstract
Full
Pdf
Sep 2003
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Oct 2003
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Nov 2003
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Dec 2003
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Jan 2004
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Feb 2004
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Mar 2004
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Apr 2004
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May 2004
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21
Jun 2004
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Jul 2004
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Aug 2004
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36
Sep 2004
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Oct 2004
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Nov 2004
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Dec 2004
15
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54
Jan 2005
20
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Feb 2005
29
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80
Mar 2005
44
137
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Apr 2005
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May 2005
16
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Jun 2005
24
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Jul 2005
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Aug 2005
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Sep 2005
24
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Oct 2005
28
116
87
Nov 2005
22
100
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Dec 2005
26
90
85
Jan 2006
20
113
87
Feb 2006
19
104
53
Mar 2006
30
127
112
Apr 2006
24
88
67
May 2006
27
112
85
Jun 2006
23
116
89
Jul 2006
19
68
69
Aug 2006
24
118
78
Sep 2006
16
159
96
Oct 2006
35
273
161
Nov 2006
28
277
198
Dec 2006
32
235
133
Jan 2007
27
264
173
Feb 2007
55
216
185
Mar 2007
40
207
180
Apr 2007
103
84
87
May 2007
84
89
98
Jun 2007
57
84
99
Jul 2007
71
137
107
Aug 2007
89
134
117
Sep 2007
89
92
103
Oct 2007
62
119
109
Nov 2007
46
64
60
Dec 2007
50
48
66
Jan 2008
64
80
79
Feb 2008
71
75
71
Mar 2008
77
70
76
Apr 2008
63
89
80
May 2008
45
67
51
Jun 2008
41
60
52
Jul 2008
63
57
47
Aug 2008
94
68
61
Sep 2008
129
83
91
Oct 2008
102
75
58
Nov 2008
89
58
56
Dec 2008
82
45
44
Jan 2009
61
49
55
Feb 2009
102
93
94
Mar 2009
80
66
59
Apr 2009
95
105
73
May 2009
59
66
79
Jun 2009
117
72
88
Jul 2009
84
52
72
Aug 2009
63
66
56
Sep 2009
61
52
37
Oct 2009
63
77
68
Nov 2009
104
63
59
Dec 2009
90
50
71
Jan 2010
76
20
56
Feb 2010
25
37
51
Mar 2010
47
21
49
Apr 2010
48
38
57
May 2010
61
64
53
Jun 2010
48
50
46
Jul 2010
61
62
67
Aug 2010
41
41
47
Sep 2010
65
55
59
Oct 2010
77
58
50
Nov 2010
63
50
55
Dec 2010
92
40
70
Jan 2011
58
51
59
Feb 2011
89
66
94
Mar 2011
76
77
68
Apr 2011
52
25
34
May 2011
45
34
42
Jun 2011
80
34
48
Jul 2011
36
29
29
Aug 2011
60
38
42
Sep 2011
65
43
50
Oct 2011
57
44
52
Nov 2011
68
83
75
Dec 2011
38
188
133
Jan 2012
60
147
122
Feb 2012
56
155
91
Mar 2012
39
163
90
Apr 2012
37
260
108
May 2012
49
346
150
Jun 2012
49
302
160
Jul 2012
59
364
151
Aug 2012
51
347
151
Sep 2012
52
351
142
Oct 2012
76
459
190
Nov 2012
87
404
153
Dec 2012
44
360
126
Jan 2013
87
526
224
Feb 2013
88
506
197
Mar 2013
68
597
192
Apr 2013
72
904
195
May 2013
77
898
218
Jun 2013
39
660
184
Jul 2013
48
653
187
Aug 2013
62
702
183
Sep 2013
44
841
241
Oct 2013
61
1023
225
Nov 2013
59
1002
313
Dec 2013
41
919
244
Jan 2014
46
930
212
Feb 2014
41
882
252
Mar 2014
52
1207
283
Apr 2014
65
1416
290
May 2014
37
1278
286
Jun 2014
56
1234
296
Jul 2014
39
761
190
Aug 2014
50
766
205
Sep 2014
54
842
189
Oct 2014
49
613
143
Nov 2014
58
805
178
Dec 2014
26
635
114
Jan 2015
52
786
183
Feb 2015
47
626
163
Mar 2015
43
845
179
Apr 2015
81
767
172
May 2015
60
996
187
Jun 2015
72
847
279
Jul 2015
102
754
229
Aug 2015
75
696
139
Sep 2015
69
831
189
Oct 2015
32
769
133
Nov 2015
55
2324
188
Dec 2015
43
842
168
Jan 2016
46
1023
217
Feb 2016
50
1042
213
Mar 2016
60
1203
242
Apr 2016
61
1433
221
May 2016
54
1393
278
Jun 2016
39
1168
235
Jul 2016
41
1013
212
Aug 2016
43
1053
202
Sep 2016
40
936
197
Oct 2016
33
1242
232
Nov 2016
65
1582
273
Dec 2016
50
1175
175
Jan 2017
60
1407
225
Feb 2017
6
943
223
Mar 2017
10
998
274
Apr 2017
9
2057
486
May 2017
14
1887
356
Jun 2017
250
1414
303
Jul 2017
568
568
160
Aug 2017
524
522
164
Sep 2017
1095
1090
230
Oct 2017
1578
1576
314
Nov 2017
1776
1768
360
Dec 2017
1326
1320
377
Jan 2018
2181
2175
489
Feb 2018
2223
2178
418
Mar 2018
2358
2350
383
Apr 2018
2490
2490
462
May 2018
2541
2544
475
Jun 2018
2652
2653
464
Jul 2018
2384
2386
475
Aug 2018
1955
1955
373
Sep 2018
2418
2418
567
Oct 2018
3346
3347
590
Nov 2018
3259
3259
601
Dec 2018
2743
2743
503
Jan 2019
3500
3479
670
Feb 2019
3241
3226
650
Mar 2019
4305
4303
732
Apr 2019
4699
4698
767
May 2019
4513
4512
779
Jun 2019
4224
4221
806
Jul 2019
3936
3949
814
Aug 2019
3898
3898
670
Sep 2019
3840
3839
725
Oct 2019
5395
5391
1047
Nov 2019
6046
6044
1041
Dec 2019
5714
5702
976
Jan 2020
6817
6808
1163
Feb 2020
6772
6768
1117
Mar 2020
7359
7358
1233
Apr 2020
8157
8152
1378
May 2020
6470
6467
1214
Jun 2020
5794
5787
898
Jul 2020
4952
4955
775
Aug 2020
5406
5380
1054
Sep 2020
6744
6737
1290
Oct 2020
9293
9272
1696
Nov 2020
10055
10044
1946
Dec 2020
9215
9199
1839
Jan 2021
9511
9497
1789
Feb 2021
8440
8419
1728
Mar 2021
4564
4548
930
Apr 2021
5064
5070
979
May 2021
6551
6561
1221
Jun 2021
5192
5198
1145
Jul 2021
4731
4743
1566
Aug 2021
7334
7347
1477
Sep 2021
9641
9656
1997
Oct 2021
11754
11758
2318
Nov 2021
12471
12473
2520
Dec 2021
8801
8986
1671
Jan 2022
9109
9823
1924
Feb 2022
8040
8710
1714
Mar 2022
11644
12497
2418
Apr 2022
10036
10771
1934
May 2022
9438
10128
2000
Jun 2022
8008
8563
1592
Jul 2022
7121
7543
1335
Aug 2022
7524
7884
1205
Sep 2022
8752
9147
1295
Oct 2022
10728
11189
1592
Nov 2022
11020
11299
1614
Dec 2022
6771
6891
1542
Jan 2023
8265
8475
1470
Feb 2023
9702
9887
1675
Mar 2023
12362
12601
1964
Apr 2023
12151
12403
1749
May 2023
14751
14989
1739
Jun 2023
10367
10611
1508
Jul 2023
13270
13496
1237
Aug 2023
9875
10055
1321
Sep 2023
11003
11188
1293
Oct 2023
11720
11865
1540
Nov 2023
12247
12391
1477
Dec 2023
22208
3012
673
Jan 2024
4690
326
106
Feb 2024
10248
674
145
Mar 2024
17301
1330
269
Apr 2024
17911
950
248
May 2024
12456
709
201
Jun 2024
8367
323
120
Jul 2024
8702
384
101
Aug 2024
5543
240
85
Sep 2024
6017
257
75
Oct 2024
6364
310
119
Total
634411
589916
112234
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