R loop over nominal list and integers - r

Question

I have a dataset where I have been able to loop over different test values with dpois. For simplicity's sake, I have used an average of 4 events per month and I wanted to know what is the likelihood of n or more events, given the average. Here is what I have managed to make work:
MonthlyAverage <- 4
cnt <- c(0:10)
for (i in cnt) {
CountProb <- ppois(cnt,MonthlyAverage,lower.tail=FALSE)
}
dfProb <- data.frame(cnt,CountProb)
I am interested in investigating this to figure out how many events I may expect each month given the mean of that month.
I would be looking to say:
For January, what is the probability of 0
For January, what is the probability of 1
For January, what is the probability of 2
etc...
For February, what is the probability of 0
For February, what is the probability of 1
For February, what is the probability of 2
etc.
To give something like (numbers here are just an example):
I thought about trying one loop to select the correct month and then remove the month column so I am just left with the single "Monthly Average" value and then performing the count loop, but that doesn't seem to work. I still get "Non-numeric argument to mathematical function". I feel like I'm close, but can anyone please point me in the right direction for the formatting?

Answer 1

a "tidy-style" solution:
library(tidyr)
library(dplyr)
## example data:
df <- data.frame(Month = c('Jan', 'Feb'),
MonthlyAverage = c(5, 2)
)
> df
Month MonthlyAverage
1 Jan 5
2 Feb 2
df |>
mutate(n = list(1:10)) |>
unnest_longer(n) |>
mutate(CountProb = ppois(n, MonthlyAverage,
lower.tail=FALSE
)
)
# A tibble: 20 x 4
Month MonthlyAverage n CountProb
<chr> <dbl> <int> <dbl>
1 Jan 5 1 0.960
2 Jan 5 2 0.875
3 Jan 5 3 0.735
4 Jan 5 4 0.560
5 Jan 5 5 0.384
6 Jan 5 6 0.238
## ...

Answer 2

How about something like this:
cnt <- 0:10
MonthlyAverage <- c(1.8, 1.56, 2.44, 1.86, 2.1, 2.3, 2, 2.78, 1.89, 1.86, 1.4, 1.71)
grid <- expand.grid(cnt =cnt, m_num = 1:12)
grid$MonthlyAverage <- MonthlyAverage[grid$m_num]
mnames <- c("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec")
grid$month <- mnames[grid$m_num]
grid$prob <- ppois(grid$cnt, grid$MonthlyAverage, lower.tail=FALSE)
grid[,c("month", "cnt", "prob")]
#> month cnt prob
#> 1 Jan 0 8.347011e-01
#> 2 Jan 1 5.371631e-01
#> 3 Jan 2 2.693789e-01
#> 4 Jan 3 1.087084e-01
#> 5 Jan 4 3.640666e-02
#> 6 Jan 5 1.037804e-02
#> 7 Jan 6 2.569450e-03
#> 8 Jan 7 5.615272e-04
#> 9 Jan 8 1.097446e-04
#> 10 Jan 9 1.938814e-05
#> 11 Jan 10 3.123964e-06
#> 12 Feb 0 7.898639e-01
#> 13 Feb 1 4.620517e-01
#> 14 Feb 2 2.063581e-01
#> 15 Feb 3 7.339743e-02
#> 16 Feb 4 2.154277e-02
#> 17 Feb 5 5.364120e-03
#> 18 Feb 6 1.157670e-03
#> 19 Feb 7 2.202330e-04
#> 20 Feb 8 3.743272e-05
#> 21 Feb 9 5.747339e-06
#> 22 Feb 10 8.044197e-07
#> 23 Mar 0 9.128391e-01
#> 24 Mar 1 7.001667e-01
#> 25 Mar 2 4.407062e-01
#> 26 Mar 3 2.296784e-01
#> 27 Mar 4 1.009515e-01
#> 28 Mar 5 3.813271e-02
#> 29 Mar 6 1.258642e-02
#> 30 Mar 7 3.681711e-03
#> 31 Mar 8 9.657751e-04
#> 32 Mar 9 2.294546e-04
#> 33 Mar 10 4.979244e-05
#> 34 Apr 0 8.443274e-01
#> 35 Apr 1 5.547763e-01
#> 36 Apr 2 2.854938e-01
#> 37 Apr 3 1.185386e-01
#> 38 Apr 4 4.090445e-02
#> 39 Apr 5 1.202455e-02
#> 40 Apr 6 3.071778e-03
#> 41 Apr 7 6.928993e-04
#> 42 Apr 8 1.398099e-04
#> 43 Apr 9 2.550478e-05
#> 44 Apr 10 4.244028e-06
#> 45 May 0 8.775436e-01
#> 46 May 1 6.203851e-01
#> 47 May 2 3.503686e-01
#> 48 May 3 1.613572e-01
#> 49 May 4 6.212612e-02
#> 50 May 5 2.044908e-02
#> 51 May 6 5.862118e-03
#> 52 May 7 1.486029e-03
#> 53 May 8 3.373058e-04
#> 54 May 9 6.927041e-05
#> 55 May 10 1.298297e-05
#> 56 Jun 0 8.997412e-01
#> 57 Jun 1 6.691458e-01
#> 58 Jun 2 4.039612e-01
#> 59 Jun 3 2.006529e-01
#> 60 Jun 4 8.375072e-02
#> 61 Jun 5 2.997569e-02
#> 62 Jun 6 9.361934e-03
#> 63 Jun 7 2.588841e-03
#> 64 Jun 8 6.415773e-04
#> 65 Jun 9 1.439431e-04
#> 66 Jun 10 2.948727e-05
#> 67 Jul 0 8.646647e-01
#> 68 Jul 1 5.939942e-01
#> 69 Jul 2 3.233236e-01
#> 70 Jul 3 1.428765e-01
#> 71 Jul 4 5.265302e-02
#> 72 Jul 5 1.656361e-02
#> 73 Jul 6 4.533806e-03
#> 74 Jul 7 1.096719e-03
#> 75 Jul 8 2.374473e-04
#> 76 Jul 9 4.649808e-05
#> 77 Jul 10 8.308224e-06
#> 78 Aug 0 9.379615e-01
#> 79 Aug 1 7.654944e-01
#> 80 Aug 2 5.257652e-01
#> 81 Aug 3 3.036162e-01
#> 82 Aug 4 1.492226e-01
#> 83 Aug 5 6.337975e-02
#> 84 Aug 6 2.360590e-02
#> 85 Aug 7 7.809999e-03
#> 86 Aug 8 2.320924e-03
#> 87 Aug 9 6.254093e-04
#> 88 Aug 10 1.540564e-04
#> 89 Sep 0 8.489282e-01
#> 90 Sep 1 5.634025e-01
#> 91 Sep 2 2.935807e-01
#> 92 Sep 3 1.235929e-01
#> 93 Sep 4 4.327373e-02
#> 94 Sep 5 1.291307e-02
#> 95 Sep 6 3.349459e-03
#> 96 Sep 7 7.672845e-04
#> 97 Sep 8 1.572459e-04
#> 98 Sep 9 2.913775e-05
#> 99 Sep 10 4.925312e-06
#> 100 Oct 0 8.443274e-01
#> 101 Oct 1 5.547763e-01
#> 102 Oct 2 2.854938e-01
#> 103 Oct 3 1.185386e-01
#> 104 Oct 4 4.090445e-02
#> 105 Oct 5 1.202455e-02
#> 106 Oct 6 3.071778e-03
#> 107 Oct 7 6.928993e-04
#> 108 Oct 8 1.398099e-04
#> 109 Oct 9 2.550478e-05
#> 110 Oct 10 4.244028e-06
#> 111 Nov 0 7.534030e-01
#> 112 Nov 1 4.081673e-01
#> 113 Nov 2 1.665023e-01
#> 114 Nov 3 5.372525e-02
#> 115 Nov 4 1.425330e-02
#> 116 Nov 5 3.201149e-03
#> 117 Nov 6 6.223149e-04
#> 118 Nov 7 1.065480e-04
#> 119 Nov 8 1.628881e-05
#> 120 Nov 9 2.248494e-06
#> 121 Nov 10 2.828495e-07
#> 122 Dec 0 8.191342e-01
#> 123 Dec 1 5.098537e-01
#> 124 Dec 2 2.454189e-01
#> 125 Dec 3 9.469102e-02
#> 126 Dec 4 3.025486e-02
#> 127 Dec 5 8.217692e-03
#> 128 Dec 6 1.937100e-03
#> 129 Dec 7 4.028407e-04
#> 130 Dec 8 7.489285e-05
#> 131 Dec 9 1.258275e-05
#> 132 Dec 10 1.927729e-06
Created on 2023-01-09 by the reprex package (v2.0.1)

Answer 3

If you have each month's mean, in base R you could easily use sapply to estimate the probability of obtaining values 0 to 10 using each month's mean value. Then you can simply combine it in a data frame:
# Data
df <- data.frame(month = month.name,
mean = c(1.8, 2.8, 1.7, 1.6, 1.8, 2,
2.3, 2.4, 2.1, 1.4, 1.9, 1.9))
probs <- sapply(1:12, function(x) ppois(0:10, df$mean[x], lower.tail = FALSE))
finaldata <- data.frame(month = rep(month.name, each = 11),
events = rep(0:10, times = 12),
prob = prob = as.vector(probs))
Output:
# month events prob
# 1 January 0 8.347011e-01
# 2 January 1 5.371631e-01
# 3 January 2 2.693789e-01
# 4 January 3 1.087084e-01
# 5 January 4 3.640666e-02
# 6 January 5 1.037804e-02
# 7 January 6 2.569450e-03
# 8 January 7 5.615272e-04
# 9 January 8 1.097446e-04
# 10 January 9 1.938814e-05
# 11 January 10 3.123964e-06
# 12 February 0 9.391899e-01
# 13 February 1 7.689218e-01
# 14 February 2 5.305463e-01
# 15 February 3 3.080626e-01
# ...
# 131 December 9 3.044317e-05
# 132 December 10 5.172695e-06