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An Investigation of the Effects of Output Variability and Output Bandwidth on User Performance in an Interactive Computer System

IP.com Disclosure Number: IPCOM000128644D
Original Publication Date: 1976-Dec-31
Included in the Prior Art Database: 2005-Sep-16

Publishing Venue

Software Patent Institute

Related People

Lawrence H. Miller: AUTHOR [+3]

Abstract

1 2. Related Topics and Areas of Study 4 3. The Experimental Approach 9 The Model 10 Confidence Intervals 12 The Parameters 12 4. Methodology 17 The System 18 The Subjects 20 Pilot Study 21 Experimental Setting 21 Data Analysis 24 Validity 25 Internal Validity ZS External Validity 28 5. Results 29 Organization of Section 30 Task Results 31 Discussion and Analysis of Test Results 36 Main Effects 37 Interaction Effects 38 Post-test Questionnaire 39 The Questions 40 Interaction Effects 44 Discussion and Analysis of Post-Test Questionnaire SO

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

An Investigation of the Effects of Output Variability and Output Bandwidth on User Performance in an Interactive Computer System

Lawrence H. Miller

ARPA ORDER NO. 2223

ISIIRR-76-50 December 1976 INFORMATION SCIENCES INSTITUTE 4676 Admiralty Way/Marinadel Rey/California 90291 UNIVERSITY OF SOUTHERN CALIFORNIA f;~7T (213 822-1511

THIS RESEARCH IS SUPPORTED BY THE ADVAT'r:ED RESEARCH PROJECTS AGENCY UNDER CONTRACT NO. DAHC1b 72 C 0308, ARPA ORDER NO. 2223, PROGRAM CODE NO. 3D30 AND 3P70. VIEWS AND CONCLUSIONS. CONTAINED IN THIS STUDY ARE THE AUTHOR'S AND SHOULD NOT BE INTERPRETED AS REPRESENTING. THE OFFICIAL OPINION OR POLICY OF ARPA, THE U.S. GOVERNMENT OR ANY OTHER PERSON OR AGENCY CONNECTED WITH THEM.

THIS DOCUMENT APPROVED FOR PUBLIC RELEASE AND SALE; DISTRIBUTION IS UNLIMITED.

CONTENTS

Abstract v

1. Introduction 1

2. Related Topics and Areas of Study 4

3. The Experimental Approach 9 The Model 10 Confidence Intervals 12 The Parameters 12

4. Methodology 17 The System 18 The Subjects 20 Pilot Study 21 Experimental Setting 21 Data Analysis 24 Validity 25 Internal Validity ZS External Validity 28

5. Results 29 Organization of Section 30 Task Results 31 Discussion and Analysis of Test Results 36 Main Effects 37 Interaction Effects 38 Post-test Questionnaire 39 The Questions 40 Interaction Effects 44 Discussion and Analysis of Post-Test Questionnaire SO

6. Conclusions and Recommendations 54 Future Studies and Extensions of Research 57

Bibliography 61

Appendices 65 1. Instructions to Subjects 65 2. Tasks to tae Performed 67 3. Post-test Questionnaire 68 4. Sample Messages 71

ABSTRACT

University of Southern California Page 1 Dec 31, 1976

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An Investigation of the Effects of Output Variability and Output Bandwidth on User Performance in an Interactive Computer System

The performance of users in man-machine interaction (MMI) is described in terms of a number of user- and machine-oriented parameters. The general linear model of experimental design is used as a model of the interaction. Performance measures are selected and a questionnaire developed to gauge user attitudes toward the man-machine system (MMS) and its environment. The interface parameters selected are hypothesized to have a significant effect on the performance and attitude measures.

The effects of varying CRT display rates and output delays upon user performance and attitudes in a series of message retrieval tasks were evaluated experimentally. The results support the somewhat surprising conclusion that doubling the display rate from 1200 to 2400 baud produces no significant performance or attitude changes; increasing the variability of the output display rate produces both significantly decreased user performance and a poorer attitude towards system and interactive environment. The generally held notion that increasing output display rates is associated with better user performance is not supported;...