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Probability of Observing At Least a Given Number of Events

Source: R/power_events_rate.R
power_events_rate.Rd

Computes the exact binomial probability of observing at least e events, for every combination of sample size and risk, and for one or more event thresholds.

Usage

power_events_rate(n, r, e)

Arguments

n

Integer or vector of integers. Sample size(s).

r

Numeric or vector of numerics. Risk(s) (per-subject event probability), between 0 and 1.

e

Integer or vector of integers. Event count threshold(s), e.g. 1, 2, 3.

Value

A matrix of class power_events_rate with columns:

N

Sample size

Risk

Per-subject event probability

>= e

One column per threshold in e, named using the "greater than or equal to" symbol followed by the threshold value, giving P(X >= e) for X ~ Binomial(N, Risk)

Examples

power_events_rate(30, 0.1, 1:3)
#> |  N | Risk |    ≥1 |    ≥2 |    ≥3 |
#> | -- | ---- | ----- | ----- | ----- |
#> | 30 | 1/10 | 95.8% | 81.6% | 58.9% |
power_events_rate(c(30, 60), c(0.05, 0.1), c(1, 2, 3))
#> |  N | Risk |    ≥1 |    ≥2 |    ≥3 |
#> | -- | ---- | ----- | ----- | ----- |
#> | 30 | 1/20 | 78.5% | 44.6% | 18.8% |
#> | 30 | 1/10 | 95.8% | 81.6% | 58.9% |
#> | 60 | 1/20 | 95.4% | 80.8% | 58.3% |
#> | 60 | 1/10 | 99.8% | 98.6% | 94.7% |