Project Blue Book Special Report No. 14: Analysis of Reports of Unidentified Aerial Objects

Special Report No. 14 was issued by the U.S. Air Force's Air Technical Intelligence Center on 5 May 1955. It is a statistical study of about 4,000 reports of unidentified aerial objects from June 1947 to December 1952. The reports were reduced to IBM punched cards and analyzed with methods including chi square tests. The report concludes that the reports it examined are very unlikely to represent technology beyond present scientific knowledge, and it notes that no case produced valid physical evidence.

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5%
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62
TABLE II
Color
CHI SQUARE TEST O|F KNOWNS VERSUS
UNKNOWNS ON THE BASIS OF COLOR
Number of
KNOWNS
Adjusted
Number of
KNQWNS (K)
Number of
UNKNOWNS (n)
White
Metallic
Not stated
Orange
Red
Yellow
Green
Blue
Other
405
313
209
172
146
128
130
67
195
Total 1765
100
77
51
42
36
31
32
17
48
434
112
76
62
49
33
31
14
26
31
434
(K-n)'
K
1.
0.
2.
1.
0.
10.
4.
6.
44
01
37
17
25
0
13
76
02
26. 15
, =