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~ 100 # equivalent to about 100
~ 100 to 200
~ 1 in 100
# also works: about 10 / roughly 50 * ~ 1 in 10
# triangular: mode 30, min 20, max 60 ~ 20 / 30 \ 60
# sample from a list (with replacement) ~ [1,2,2,3,3,3]
# find the best fit to centile values # (5th, 50th and 95th by default) ~ 1 | 10 | 100
# fit to specific centiles ~ 25th@10 | 50th@12 | 75th@17
# with constraints
~ 1 | 10 | 100 {>0, <120}
# Examples of all the different distributions
# Assumed
~ 10
~ 10 {count}
~ 10 {norm}
~ 1/10\20
~ 1 in 10
# FITTED by quantile values
# Normal distribution
~ 10 | 20 | 30
# log normal (found to be the best fit)
~ 0 | 5 | 30
# log normal (forced)
~ 0 | 2 | 10 {lognorm}
# Forced gamma
~ 0 | 5 | 100
# Weibull distribution
~ 5th@4 | 50th@10 | 95th@14
# t dist
~ 5th@10 | 25th@80 | 50th@100 | 75th@120 | 95th@190
Fun examples!
# the flake equation # https://xkcd.com/718/ Wp = ~ 8 * 10 ^ 9 # world pop. # fraction people who imagine aliens to feel special Cr = ~ 1 in 10000 # fraction people who mistake natural phenom for aliens Mx = ~ 1 in 10000 # p(tell someone) Tk = ~ 1 in 50 F0 = ~ 5 # number people they tell F1 = ~ 5 # n who retell # prob. details revised Dt = ~ 99 in 100 # fraction with means to publicise Au = ~ 1 in 100 number_of_credible_alien_sightings = Wp * (Cr + Mx) * Tk * F0 * F1 * Dt * Au
Wp = ~ 7.9e9 to 8.1e9 # world pop.
Sneezes_per_day = ~ .2 |2 | 20 {>0, <100}
Seconds_per_day = 24*60*60
proportion_day_awake = .75
sneezes_per_second = (Wp * Sneezes_per_day) / Seconds_per_day* proportion_day_awake
# are there more than 1m per second?
sneezes_per_second > 1e6
Wp = ~ 7.9e9 to 8.1e9 # world pop. Awake = ~ 7 in 10 Outdoors = ~ 2 in 10 Happy = ~ 1 in 10 CanWhistle = ~ 1 in 2 DoWhistle = ~ 1 in 100 number_people_currently_whistling = Wp * Awake * Outdoors * Happy * CanWhistle * DoWhistle
# holiday budget
food_cost = ~20 / 25 \ 70 # Daily £, pp
flight = ~200
hotel = ~80 / 120 \ 180
days = ~5 {>3}
total_cost = (food_cost * days * 2) + flight + (hotel * days)
total_cost < 1500
More serious examples:
# Simplified drug development decision model # Phase 2 success probability (Wong et al., 2019) phase2_success = ~28 in 100 # Development cost in millions development_cost = ~80 / 150 \ 300 # Market potential if successful market_value = ~ 25th@300 | 50th@500 | 90th@1200 pipeline = ~8 potential_return_millions = pipeline * phase2_success * (market_value - development_cost)
# Monetary cost of climate damage caused by a typical # shorthaul flight, using a social cost of carbon approach. # Round trip distance, including overhead typical_km = ~ 1000 ... 3000 # industry figures kg_co2_per_km = ~ 0.22 / 0.25 \ 0.30 # for radiative forcing, # DEFRA/IPCC suggest multiplier of 1.7 to 2.0 rf_multiplier = ~ 1.5 to 2 # social cost of carbon; # convert £/tonne to £/kg scc = (~ 50 to 100) / 1000 # totals emissions = typical_km * kg_co2_per_km total_cost_gbp = emissions * rf_multiplier * scc
# savings from reducing burnout in employees
burnout_rate = ~ .01 / .02 \ .05 # annual %
loss_per_person = ~ 10@500 | 50@1000 | 95@5000 {>250}
N = 8000 # n employees
tx_reduces_burnout_by = ~ .0 to .02
current_costs = burnout_rate * loss_per_person * N
new_costs = (burnout_rate - tx_reduces_burnout_by) * loss_per_person * N
savings_from_tx = current_costs - new_costs
A simple calculator for things you're not sure about.
~TimesUncertain is a simple calculator for things you're not sure about. It is a teaching tool for students learning about probability. Please don't use this for anything important without checking the results carefully! Developed by Ben Whalley and hosted by Plymouth University