1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 % TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%0(/.%G0G0.%47/2+G0G0!.$G0G0)3$.15!,)49G0G0/&G0G03%26)#% G0G0.%47/2+G0G0-!.!%-%.4!.$G0G042!&)#G0G0%.).%2).#/,%#4)/.G0G0!.$G0G034!4)34)#!,G0G0!.!,93)3/&G0G030%#)!,G0G015!,)49G0G0/&G0G03%26)#%/“3%26!4)/.G0G0
2、4!G0G0&/2G0G0-%!352%-%.43/&G0G0#534/-%2G0G0$)&)#5,4)%3G0G0).G0G04(%).4%2.!4)/.!,G0G0!54/-!4)#G0G03%26)#%)45G134G0G0RecommendationG0G0% (Extract from the “LUEG0“OOK)NOTES1 ITU-T Recommendation E.427 was published in Fascicle II.3 of the Blue Book. This file is an extract from theBlue Book. While th
3、e presentation and layout of the text might be slightly different from the Blue Book version, thecontents of the file are identical to the Blue Book version and copyright conditions remain unchanged (see below).2 In this Recommendation, the expression “Administration” is used for conciseness to indi
4、cate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic ormechanical, including photocopying and microfilm, without permission in writing from t
5、he ITU.Fascicle II.3 - Rec. E.427 1Recommendation E.427Fascicle II.3 - Rec. E.427COLLECTION AND STATISTICAL ANALYSIS OF SPECIAL QUALITY OF SERVICE OBSERVATION DATAFOR MEASUREMENTS OF CUSTOMER DIFFICULTIES IN THEINTERNATIONAL AUTOMATIC SERVICEThis Recommendation is provided to permit the orderly coll
6、ection of data required for special studies toidentify sources of difficulty in customer use of the international automatic telephone service.When calls are made to points outside a customers home country, many different sets of ringing and busy tonesare encountered. In order to measure the effect o
7、f unusual sounding ringing tones and busy tones on customerbehaviour, it has been decided to collect data on how long customers listen to such foreign tones as well as to theirnational tones in order to compare them.The data are to be collected in the same manner as those required for the completion
8、 of Table 1/E.422. Thesedata are an extension of those collected for Table 1/E.422, and, as an aid to subsequent analysis, a copy of the currentversion of that table should be used with the table of this Recommendation.Table 1/E.427 contains questions numbered 1-9. Their relationship to the question
9、s of Table 1/E.422 is shownin parentheses.A preferred set of analyses for identifying the statistical significance of differences between data collected fromsubscribers when setting up national calls and the corresponding data collected from subscribers when setting upinternational calls is given be
10、low.1 Determine the percentage change in any measure by use of the formula:()Change CfNfNiijjiHH=100j = A, B, Ci = 0-2, 2-5 ., 30whereijis the observed frequency of calls of category i in the country j,Njis the total number of observations in the country j sample,iHis the observed frequency of calls
11、 of category i in the home country H, andNHis the total number of observations in the home country sample.2 Compare the central location of the distributions by use of the Kruskal-Wallis One-Way Analysis ofVariance 1.3 Compare the “forms“ or “shapes“ of the distribution by means of the chi-square te
12、st 2.4 Compare changes in single valued variables, e.g. percentage incomplete-trunk-code, by use the chi-square test.2 Fascicle II.3 - Rec. E.427TABLE 1/E.427(Supplement to Table 1/E.422)Observations of international outgoing telephone calls for quality of serviceAdditional details regarding subscri
13、ber dialled callsOutgoing international exchange: Group of circuits:Period from: . to .Category Number PercentageSubtotal Total Subtotal TotalDetails of dialled callsa)b)c)1. Calls with errors in the dialled numberd)1.1(6.1) Wrong number dialled.1.1.1 Wrong country code .1.1.2 National trunk prefix
14、e.g. “0”) wrongly included .1.1.3 Wrong trunk code 1.1.4 Wrong subscriber number 1.2(6.2) Incomplete number dialled .1.2.1 National (significant) number not dialled or incomplete .1.2.2 Trunk code not dialled or incomplete1.2.3 Subscriber number not dialled or incomplete.1001002. (5.3) Calls abando
15、ned prematurely before receipt of a tone or(6.3) announcement Interval from end of dialling to disconnecte) :0- 5 s 5- 10 s .10-20 s .20-30 s .30-50 s . 50 s .1003. Post dialling delay on all calls that are maintained beyond the start of a tone or announcement .Interval from end of dialling to tone
16、or announcement:0- 5 s .5- 10 s 10- 20 s 20- 30 s 30- 60 s 60- 90 s 90 s Average excluded portionf). . .100Fascicle II.3 - Rec. E.427 34. Calls that encounter ringing tonesg)4.1(1) Completed calls .Interval from beginning of tone to answer:0- 10 s 10- 20 s 20- 30 s 30- 50 s 50 s.4.2(2.6.4) Incomplet
17、e callsInterval from beginning of tone to disconnect:0- 10 s 10- 20 s 20- 30 s 30- 50 s 50 s .1001005.(3.2) Calls that encounter busy/congestion tonesg)Interval from beginning of tone to disconnect:0- 2 s 2- 5 s 5-20 s 20-30 s. 30 s.1006.(4.2) Calls that encounter tones that the observer cannot iden
18、tify Interval from beginning of tone to disconnect:0- 2 s2- 5 s .5-10 s .10-30 s . 30 s.1007.(3.3,4.3) Calls encountering recorded announcements .Interval from beginning of announcement to disconnect:0- 10 s .10- 20 s .20- 30 s . 30 s .1008. List types of errors in dialling and tone interpretation w
19、hich could not be categorized.9. List restrictions on subscriber sampleh).a)The term “calls“ throughout this table refers to circuit seizures by outgoing traffic.b)The data for each called country should be collected separately and not combined with other countries.c)The interpretation of these resu
20、lts cannot be made adequately except by comparing them with similar results on national calls.d)The practicability of putting the observation in category 1 will depend upon the observation access point and knowledge of thenational numbering plan of the outgoing country and of the destination country
21、e)0- 5 s implies 0 t 5.5-10 s implies 5 t 10.f)The “post-dialling delay“ measurements may not represent the actual delay from the time the subscriber finishes dialling to thereceipt of tone. To the extent that this measurement as observed on the trunk excludes the time from completion of dialling t
22、oseizure of trunk, the average duration of this excluded time should be reported.4 Fascicle II.3 - Rec. E.427g)Identification of tone categories should be made by service observers who are trained to identify the tone categories reliably.h)If access to the trunks being observed is restricted to some
23、 specified population of subscribers, e.g., heavy users, non-coin users,or residents of large urban centres, such restrictions should be noted and reported with the service observations.References1 MARASCUILO (L. A.), McSWEENEY (M.): Non-Parametric and Distribution-Free Methods for the SocialSciences, Wadsworth Publishing Co., California, 1977.2 SIEGEL (S.): Non-Parametric Statistics for the Behavioural Sciences, McGraw Hill, New York, 1956.
