Contents Telektronikk - Telenor

Table 7 Call holding times (in minutes) – Interval 2: Weekdays 1700–0800
a The charging data files do not show the actual holding times if they are longer than 600 minutes (10 hours). However, TELMAX
will generate their own reports if such long conversations occur
(1.6 – 1.7), and for calls to neighbouring
counties where the C.D. is smaller (1.3,
with few samples). It is also quite natural
that the categories of Fax, Paging, Special
services and Toll-free numbers have
their own special characteristics.
3.5.2 Interval 2: Weekdays
between 1700 and 0800
This interval is outside the normal working
hours, and the number of calls is
much lower – less than 10 % of that during
Interval 1, although the observation
time is longer.
Figure 8 shows the distribution of call
holding times for all outgoing calls in
Interval 2 (Period 1), in the same way as
that for Interval 1 (Figure 7).
Like Figure 7, Figure 8 shows a clear
concentration of holding times in the
lower part of the histogram. Figure 8
shows that the call holding time is even
more scatted in Interval 2 than that in
Interval 1. The standard deviation (15.04
min.) is more than 3 times as large as the
mean (4.93 min.).
The mean holding time is, as expected,
clearly longer than that in Interval 1, due
to less time pressure and (for most of the
categories) lower price.
Table 7 shows numbers of observations,
mean values, standard deviations, coefficients
of variation, and maximum holding
times for all successful outgoing calls
Period 1 Period 2
Category # obs Mean S.D. C.V. Max. # obs Mean S.D. C.V. Max.
Local 5769 3.71 7.67 2.07 164.7 6591 3.81 8.41 2.21 191.5
Neighb.counties 65 6.33 7.29 1.15 32.1 57 7.29 7.26 1.00 33.8
Long distance 1576 10.05 30.34 3.02 600.0a 1498 9.30 11.96 1.29 91.8
Universities 35 7.10 12.15 1.71 53.3 26 3.73 8.26 2.21 40.2
Univ. (fax) 17 1.53 1.22 0.80 5.0 7 2.11 2.18 1.03 6.8
International 497 5.81 9.97 1.72 110.0 577 5.91 10.67 1.81 96.1
Mobile 68 3.16 4.61 1.46 19.0 80 2.62 4.81 1.84 22.7
Paging 19 0.39 0.21 0.54 0.8 60 0.38 0.12 0.32 0.9
Special serv. 427 1.67 3.66 2.19 32.7 511 1.57 3.85 2.45 50.1
Toll-free 12 11.40 13.89 1.22 44.2 27 12.07 12.07 1.00 43.7
Total 8433 4.93 15.04 3.05 600.0 9401 4.70 9.27 1.97 191.5
and for each category, for both of the
observation periods.
Since the number of observations is
much lower in this interval than that in
Registered number of calls
10 000
9 000
8 000
7 000
6 000
5 000
4 000
3 000
2 000
1 000
0
0
Interval 1, the results shown in Table 7
are probably more influenced by statistical
fluctuations. For example in Period 1
the single conversation which has the
longest holding time (registered with a
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23>24
Minutes
Figure 7 Call holding times, Period 1, Interval 1
Number of observations: 103717 Mean: 3.26 mins
Standard deviation: 5.13 mins Maximum holding time: 263.4 mins
125