(Analysis of Reports of Unidentified Aerial Objects)

This CIA-released copy of Project Blue Book Special Report No. 14 is dated 5 May 1955 and comes from the Air Technical Intelligence Center at Wright-Patterson Air Force Base. It is a statistical analysis of about 4,000 unidentified aerial object reports from 1947 through 1952, coded onto IBM punched cards with the help of a panel of scientists. The report concludes that such objects were highly unlikely to be technological developments beyond present-day scientific knowledge. It also found no valid evidence of physical matter.

TABLE V CHI SQUARE TEST OF KNOWNS VERSUS UNKNOWNS ON THE BASIS OF DURATION OF OBSERVATION

Duration of Observation	Number of KNOWNS	Adjusted Number of KNOWNS(K)	Number of UNKNOWNS(n)	X2(K-n)2/K
5 sec or less	259	64	27	21.39
6-10 sec	92	23	21	0.17
11-30 sec	153	38	33	0.66
31-60 sec	108	26	42	9.85
61 sec-5 min	269	66	99	16.50
6-30 min	305	75	71	0.21
Over 30 min	135	33	37	0.48
Not stated	444	109	104	0.23
Total	1765	434	434	49.49
Degrees of freedom	7
5% 14.1
1% 18.5