D-K Statistical Slide Rule
date: label: date made
content: 1933
name: label: publisher
content: Psychological Corporation
notes: label: Description
content: This is one of several slide rules designed for use in psychology. It has a white plastic envelope that holds a paper slide. The upper part of the envelope has scales labeled A (a 23-centimeter ruler, divided to millimeters), N (number of cases), PE (probable error, running from 1 to 10), sigma (running from 1 sigma to 10 sigma), and c (probability that an event happened by chance). The top part of the slide has scales labeled r (running from 0.97 down to 0.00, divided logarithmically) and B (logarithmically divided from 0.05 to 0.20).
label: Description
content: The lower part of the envelope has scales labeled sigma (standard deviation) and D (a standard slide rule logarithmic scale for multiplication, running from 10 to 140). The lower part of the slide has scales labeled sigma<sub>1.2</sub>, sigma<sub>M</sub> (standard error of measurement), and C (divided logarithmically and running from 10 to 140). The center of the slide has the line graph r<sub>1/2 /III</sub> to r<sub>1I</sub>. The back of the envelope has five more line graphs.
label: Description
content: Instructions are provided on the back of the slide and on a leaflet received with the rule. The lower left corner of the envelope is marked: Designed by Jack W. Dunlap and Albert K. Kurtz. The lower right corner is marked: Copyright 1933 by The Psychological Corporation. James McKeen Cattell, Robert Sessions Woodworth, and Edward Lee Thorndike founded the Psychological Corporation in New York City in 1921 to market psychological tests and educational materials. Jack W. Dunlap (1902–1977) and Albert Kenneth Kurtz (1904–1992) were academic psychologists interested in graphic computation charts. They copyrighted the D-K Statistical Slide Rule again in 1938, after which it was sold as a duplex wooden rule. After World War II, Dunlap went into industrial psychology.
label: Description
content: References: advertisement, <i>Science</i> 79, no. 2041 (February 9, 1934), back matter, 7; Library of Congress Copyright Office, <i>Catalog of Copyright Entries: Part 1, Books, Group 2, Pamphlets, Etc.</i>, n.s. 31 (1935): 24; Jack W. Dunlap and Albert K. Kurtz, <i>Handbook of Statistical Nomographs, Tables, and Formulas</i> (Yonkers-on-Hudson, N.Y.: World Book Company, 1932); Albert K. Kurtz, "Obituary: Jack W. Dunlap," <i>American Psychologist</i> 34, no. 6 (June 1979): 538; J. McKeen Cattell, "The Psychological Corporation," <i>Annals of the American Academy of Political and Social Science</i> 110 (November 1923): 165–171.
label: Location
content: Currently not on view
place: label: place made
content: United States: New York, New York City
topic: label: Subject
content: Mathematics
label: Subject
content: Rule, Calculating
label: Subject
content: Psychology
label: Subject
content: Statistics
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Science & Mathematics
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content: Slide Rules
creditLine: label: Credit Line
content: Gift of Oscar W. Richards
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1979.3074.04
label: nonaccession number
content: 1979.3074
label: catalog number
content: 1979.3074.04
objectType: label: Object Name
content: slide rule
label: Object Name
content: calculating rule
physicalDescription: label: Physical Description
content: plastic (overall material)
label: Physical Description
content: paper (part material)
label: Measurements
content: overall: .2 cm x 26.8 cm x 15.3 cm; 3/32 in x 10 9/16 in x 6 1/32 in