Mathematical calculation

Felicia Venn <>
Thu May 18 19:39:13 CEST 2000

please could you send me the syntax for calculating an 'average delay for
all calls' using the (Erlang table)

I have attached the work which this question is related to.  Please send
me an answer as soon as possible because i need this information urgently

Thank you

Alternative e-mail address:

This memo addresses the issue of staffing support levels currently in
practice at the SNB university. Having reviewed the last interview notes
regarding this issue, there is reason to believe that some errors were
made in the assessment.  In particular, regarding the maximum waiting time
on calls to the helpdesk.  The following calculations indicate the correct
level of staff required by the helpdesk to provide more efficient levels
of service support.

Call volume 				= 42 calls/ hours 
Average call length 			= 10 minutes
Maximum waiting time 		= 1 minute

The PFM staff support workload works out as follows:

A 	Workload 		=  (10 * 42)/60
				=     420    /60
				=  7 Erlangs

B	The ADDC (Average Delay of Delayed calls) Factor works out

	ADDC factor		= 1/ 10
				= 0.1

C	Using the Erlang Table: The amount of staff required = 17, Delayed	
	Portion = 0.0010

D	So Percentage of delayed calls  = ? %

E	ADDC (Average delay of Delayed calls) :

	- The ADDC factor from table          = 0.1
	- The average call length in seconds  = 10 minutes * 60 (seconds)	
					      = 600

	So ADDC 			    = 600 * 0.1
		  			    = 60 seconds
					    = 1 minute

F	'Average delay for all calls' 	    = ?

The mathematical evidence above shows that staff levels are of priority
and that the existing  staff levels are not adequate enough to handle the
current level of support calls to the helpdesk.  Therefore an increased
number of staff are required to work around the help desk which could help
eradicate the majority of all call delays to the helpdesk.

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