Line graph with 95% confidence interval band-CodePudding

Hi I'm trying to produce a line graph to show the changes in average monthly costs for people in the treatment and the control groups before a specific date. My data looks like this

ID <- c("A", "B", "C", "D", "E", "F")
Treatment <- c(1, 1, 1, 0, 0 ,0)
last_3_month <- c(300, 300, 400, 0, 100, 20)
last_2_month <- c(400, 600, 500, 10, 40, 30)
last_1_month <- c(300, 600, 600, 20, 30, 40)

df <- data.frame(ID, Treatment, last_3_month, last_2_month, last_1_month)

  ID Treatment last_3_month last_2_month last_1_month
1  A         1          300          400          300
2  B         1          300          600          600
3  C         1          400          500          600
4  D         0            0           10           20
5  E         0          100           40           30
6  F         0           20           30           40

In addition to the mean cost of each month, I also want to plot the 95% confidence interval for each month. In this example, the means and the intervals are:

  Treatment       last_3_month     last_2_month     last_1_month
          0           40               26.67             30
                [-91.45 171.45]   [-11.28 64.61]    [5.16 54.84]
          1          333.33            500              500
                [189.91 476.76]   [251.59 748.41]   [69.73 930.27]

where numbers in each cell are means, and those in the square brackets are the 95% confidence intervals. I calculated these values by using the command t.test.

I would like to produce a graph where X axis denotes months before the specific date, and Y axis denotes costs. There should be two lines connecting the mean values of the monthly costs along with the 95% confidence interval for the treatment and the control groups separately.

I would be really grateful for your help on this.

CodePudding user response：

Is this what you're looking for using the output from your t.test?

You could look at the Broom package which has tidiers for various test outputs.

library(tidyverse)

tribble(
  ~treatment, ~measure, ~last_3_month, ~last_2_month, ~last_1_month,
  0, "mean", 40, 26.67, 30,
  0, "lower", -91.45, -11.28, 5.16,
  0, "upper", 171.45, 64.61, 54.84,
  1, "mean", 333.33, 500, 500,
  1, "lower", 189.91, 251.59, 69.73,
  1, "upper", 476.76, 748.41, 930.27
) |>
  pivot_longer(-c(treatment, measure)) |>
  pivot_wider(names_from = measure, values_from = value) |> 
  mutate(
    name = factor(name),
    treatment = str_c("Treatment ", treatment)
  ) |>
  ggplot(aes(name, mean, colour = treatment, group = treatment))  
  geom_ribbon(aes(ymin = lower, ymax = upper), fill = "grey90")  
  geom_line()

^{Created on 2022-04-27 by the reprex package (v2.0.1)}