Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Calculate travel time standard deviations #161

Draft
wants to merge 5 commits into
base: min-bins
Choose a base branch
from
Draft

Calculate travel time standard deviations #161

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
9c6318b
recalculate mean, add standard deviation
Nate-Wessel Nov 27, 2024
b5d806c
report corridor length in meters
Nate-Wessel Nov 27, 2024
285eb46
Merge branch 'min-bins' into standard-deviation
Nate-Wessel Nov 27, 2024
bd55abe
ooooops, average SQUARED deviation from the mean
Nate-Wessel Nov 27, 2024
ec9be2a
N-1 for sample stat
Nate-Wessel Nov 27, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 3 additions & 0 deletions frontend/src/corridor.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,9 @@ export class Corridor extends Factor {
}
get segments(){ return this.#segments }
get links(){ return this.segments.flatMap( seg => seg.links ) }
get length_in_meters(){
return this.links.reduce((cs,link)=>cs+link.length_m, 0)
}
get viaStreets(){
return new Set( this.links.map( link => link.name ) )
}
Expand Down
17 changes: 15 additions & 2 deletions frontend/src/travelTimeQuery.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -78,8 +78,21 @@ export class TravelTimeQuery {
this.holidaysAreRelevant ? this.#holidayOption.holidaysIncluded : 'NA'
)
record.set('hoursInRange', this.hoursInRange)
record.set('mean_travel_time_minutes', this.#results?.travel_time?.minutes)
record.set('mean_travel_time_seconds', this.#results?.travel_time?.seconds)
// get the standard deviation of the travel time observations
// start by calculating the mean again, separately
// this is because the tt means we use aren't straight averages, for historical reasons
let sum_obs = this.#results.observations.reduce((cumsum, tt) => {
return cumsum + tt.seconds
}, 0)
let mean_obs = sum_obs / this.#results.observations.length
record.set('mean_travel_time_seconds', mean_obs)
// sum of the squared deviations from the mean
let sum_sq_dev = this.#results.observations.reduce((cumsum, tt) => {
return cumsum + (mean_obs - tt.seconds)**2
}, 0)
let sample_variance = sum_sq_dev / (this.#results.observations.length - 1)
record.set('tt_sd_seconds', Math.sqrt(sample_variance))
record.set('length_in_meters', this.corridor.length_in_meters)
// turning these off in the frontend until they're ready for production
//record.set('moe_lower_p95', this.#results?.confidence?.intervals?.['p=0.95']?.lower?.seconds)
//record.set('moe_upper_p95', this.#results?.confidence?.intervals?.['p=0.95']?.upper?.seconds)
Expand Down