§ 83.01 – What expansion factor should I use for the APTL option?

(a)    You must use your 100% count of UPT as the expansion factor.

(b)   For estimating average daily PMT by type of service days, use your annual total 100% count of UPT by type of service days.

(c)    For estimating annual total PMT:

(1)   Use your annual total 100% count of UPT if your sampling plan is not based on grouping.

(2)   Use your annual total 100% count of UPT by service group if your sampling plan is based on grouping and you have reliable 100% counts of UPT by service group and have entered information into the template accordingly in developing your current template sampling plan.  Refer to cell M52 of the PeriodInput Worksheet in the template you used in developing your current period-based template sampling plan, and it should be 1.

(3)   Use your annual total 100% count of UPT if your sampling plan is based on grouping but you do not have reliable 100% counts of UPT by service group and you have entered information into the template accordingly in developing your current period-based template sampling plan.  Refer to cell M52 of the PeriodInput Worksheet in the template you used in developing your current period-based template sampling plan, and it should be 0.

§ 83.03 – What sample ratio should I use for the APTL option?

(a)    You must use the sample APTL as the sample ratio.

(b)   Use sample APTL by type of service days for estimating average daily PMT by type of service days.  If your sample happens not to include service unit for a particular day type (e.g., Saturday), use the sample APTL for the entire sample for this day type. 

(c)    For estimating annual total PMT:

(1)   Use sample APTL for the entire sample if you do not group your service.

(2)   Use sample APTL for each group if your sampling plan is based on grouping and you have reliable 100% counts of UPT by service group and have entered information into the template accordingly in developing your current period-based template sampling plan.  Refer to cell M52 of the PeriodInput Worksheet in the template you used in developing your current period-based template sampling plan, and it should be 1.

(3)   Use weighted sample APTL for the entire sample if your sampling plan is based on grouping but you do not have reliable 100% counts of UPT by service group and you have entered information into the template accordingly in developing your current period-based template sampling plan.  Refer to cell M52 of the PeriodInput Worksheet in the template you used in developing your current period-based template sampling plan, and it should be 0.

§ 83.05 – How should I determine the APTL from my sample?

(a)    You must determine the sample APTL for a given sample as the ratio of sample total PMT over sample total UPT for the following cases:

(1)   for the entire sample,

(2)   by type of service days, or

(3)   by service group if applicable.

(b)   You must not determine the sample APTL as the average of the APTL across individual service units in the sample.

(c)    To determine the weighted sample APTL for an entire sample as required by question §83.03(c)(3), you should follow these steps:

(1)   Determine each group’s size in the number of service units actual operated.

(2)   Compute each group’s share of the number of service units actually operated.  These shares must sum to 1.

(3)   Determine each group’s sample size in the number of service units in the sample.

(4)   Determine each group’s sample total UPT.

(5)   Determine each group’s sample total PMT.

(6)   Compute each group’s sample average for UPT.

(7)   Compute each group’s sample average for PMT.

(8)   Sum the product of each group’s share of the number of service units actually operated and its sample average UPT.

(9)   Sum the product of each group’s share of the number of service units actually operated and its sample average PMT.

(10)           Compute the ratio of the result from (9) to the result from (8).  This ratio gives the weighted sample APTL.

(11)           Table 83.01 shows these steps with an example.

Table 83.01.  Example of Estimating Weighted Sample APTL

Step

 Description

Service Groups

Short Routes

Medium Routes

Long Routes

1

Group size in service units

109,685

331,033

35,325

2

Group size in shares

0.2304

0.6954

0.0742

3

Sample size

116

386

47

4

Sample total UPT

1,157

8,181

1,592

5

Sample total PMT

3,989

42,966

7,003

6

Sample average UPT

10.0

21.2

33.9

7

Sample average PMT

34.4

111.3

149.0

8

Weighted sample average UPT

19.55

9

Weighted sample average PMT

96.38

10

Weighted sample APTL

4.93

§ 83.07 – How should I estimate annual total PMT for the APTL option?

(a)    If your sampling plan is not based on service grouping, you should multiply your sample APTL for the entire annual sample with your corresponding annual expansion factor (i.e., 100% count of annual UPT) to get an estimate of the annual total PMT.

(b)   You should take a two-step approach if your sampling plan is based on service grouping and you have reliable 100% counts of UPT by service group:

(1)   Multiply your sample APTL with your corresponding expansion factor for each group, and

(2)   Sum the above products across all groups to get your annual total PMT.

(c)    If your sampling plan is based on service grouping but you do not have reliable 100% counts of UPT by service group, you should multiple your weighted sample APTL as computed in question §83.05 with your 100% count of annual UPT.

(d)   If your sampling plan is based on service grouping, refer to cell M52 of the PeriodInput Worksheet in the template you used in developing your template sampling plan for what you have entered into cell M52 on whether you have reliable 100% count of UPT by service group.

§ 83.09 – How should I estimate average daily PMT by type of service days?

(a)    If you operate your service only on weekdays, all you need to do is to divide your estimated annual total PMT by the number of typical weekday days of service.

(b)   If you operate your service on Saturdays, Sundays, or both as well, you should take the following two steps:

(1)   Multiply your sample average APTL for each type of service days with the corresponding 100% count of UPT to get the annual total PMT for each type of service days.

(2)   Divide the estimated annual total PMT for each type of service days by the corresponding number of typical days for each type of service days.