Project Blue Book Special Report (second copy)

This is Project Blue Book Special Report No. 14, "Analysis of Reports of Unidentified Aerial Objects," Project No. 10073, dated 5 May 1955. The study reduced about 4,000 sighting reports received by the U.S. Air Force between June 1947 and December 1952 to IBM punched cards and analyzed them statistically, including chi square tests comparing knowns with unknowns. It concludes that the reports very probably do not represent technological developments beyond present scientific knowledge, and it notes that no case produced physical evidence.

TABLE IX CHI SQUARE TEST OF REVISED KNOWNS VERSUS
UNKNOWNS ON THE BASIS OF NUMBER
Number of
Objects Per
Sighting
Number of
KNOWNS
Adjusted
Number of
KNOWNS (K)
Number of (K-n):
[OWN
297
37
70
25
5
S(n) K
0 .
2 .
2 .
15.
2 .
39
52
96
36
50
1
2
3-10
11 or more
Not stated
913
142
168
34
29
308
4 8
57
11
10
Total 1286 434 434 23. 73
D e g r e e s of f r e e d o m
5%
1%
9. 5
13.3
71
! ; • ••