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

United States Air Force, Air Technical Intelligence Center · 1955-05-05 · 309 pages · text from the file's own layer

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.

Open the PDF at page 73 Original source ↗

“multiple objects”5 pages

  • p. 17 …Therefore, a designation of OBJECT SIGHTINGS was established, with the following definition: OBJECT SIGHTING - (1) The…
  • p. 18 …An example was the finding of the approxi- mate angular velocity and acceleration of the object…
  • p. 23 …the reported color of the objects, because of the multiplicity of reports on some of the…
  • p. 76 …a greater proportion of UNKNOWNS in the multiple object classification. Apparently these are harder to identify…
  • p. 299 …Unit sightings, single observers Unit sightings, multiple observers Object sightings X Y 0 1 2 3…
TABLE V CHI SQUARE TEST OF KNOWNS VERSUS UNKNOWNS
ON THE BASIS OF DURATION OF OBSERVATION
Duration of
Observation
5 sec or less
6-10 sec
11-30 sec
31-60 sec
61 sec-5 min
6-30 min
Over 30 min
Not stated
Number of
KNOWNS
259-"
92
153
108
269'
305
135
444
Adjusted
Number of
KNOWNS (K)
64
23
38
26
66
75
33
109
Number of
UNKNOWNS (n)
27
21
33
42
99
71
3 7 l
104
X 2
(K-n)2
K
21.39
0. 17
0.66
9.85
16. 50
0.21
. 0.48
0.23
Total 1765 434 434 49.49
# Degrees of freedom
5%
1%
14. 1
18. 5
65
it I

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Analysis, from the classic collection. The PDF is mirrored here; the original link is under it. 309 pages are in the text index: search them above, or from the library's search.