§ 81.01 – What service-consumed data must I estimate with 100% UPT?

(a)    You must estimate PMT.

(b)   The following table shows the data items you must estimate.

Table 81.01.  Service-Consumed Data Items with 100% UPT

If your sampling plan is based on the

you must estimate

APTL option

·  annual total PMT

·  average daily PMT by type of service days

PPMT option

·  annual total PMT

·  average daily PMT by type of service days

§ 81.03 – What do I need to do in general to get estimates of these data items?

(a)    You must determine expansion factors.

(b)   You must determine sample ratios.

(c)    You must combine the expansion factors and sample ratios to get the corresponding estimates of service-consumed data.

§ 81.05 – What is a sample ratio?

(a)    A sample ratio is the ratio between the sample total of one measure of service-consumed and the sample total of another measure of service-consumed.  This Sampling Manual uses two sample ratios:

(1)   The ratio of sample total PMT over sample total UPT gives the sample APTL.

(2)   The ratio of sample total PMT over sample total PPMT gives the sample PMT/PPMT ratio.

(b)   They may be calculated for the entire annual sample or by the type of service days.

§ 81.07 – What is an expansion factor when I have 100% UPT?

(a)    A measure of actual services consumed during a given duration of time. 

(b)   It is used to convert sample ratios to totals in the given duration.  A 100% count of UPT consumed during an entire year is an example of an expansion factor in service consumed; when multiplied by sample APTL, it yields a measure of annual total PMT.