Q:

Using geom_line and geom_point for different series in one facet

I'm using ggplot2 to create a plot like the following one:

The problem I'm encountering is combining points and lines in the upper facet. As in the image, I want means to be represented by lines and the data by points.   
I can produce lines for both the means and the data using geom_line and putting the means and data in one group, and the probabilities in another, as seen here:

But I cannot combine lines and points in a single facet. Because of this, I didn't reshape the data provided below nor group them.      
years <- c(1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969)
a.data <- c(0.105, 0.075, 0.107, 0.112, 0.116, 0.062, 0.044, 0.073)
b.data <- c(-0.039, -0.022, -0.070, -0.062, -0.067, -0.065, -0.023, -0.015)
a.mean <- c(0.0893, 0.0893, 0.0893, 0.0893, 0.0893, 0.0763, 0.0757, 0.0757)
b.mean <- c(-0.040, -0.040, -0.040, -0.040, -0.040, -0.030, -0.029, -0.029)
prob <- c(0.0, 0.0, 0.0, 0.0, 0.348 0.020, 0.002, 0.0)

Any assistance would be greatly appreciated. 

A:

Trying to solve your problem I find my way to do the plot, not with diferent facet but with two graph in the same grid, using the package gridExtra.
As you can see, I had to restore the data in diferent objet to do each part of the plot.
resulting_plot
library(tidyverse)
library(gridExtra)

data <- data.frame(
        years = c(1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969),
        a.data = c(0.105, 0.075, 0.107, 0.112, 0.116, 0.062, 0.044, 0.073),
        b.data = c(-0.039, -0.022, -0.070, -0.062, -0.067, -0.065, -0.023, -0.015),
        a.mean = c(0.0893, 0.0893, 0.0893, 0.0893, 0.0893, 0.0763, 0.0757, 0.0757),
        b.mean = c(-0.040, -0.040, -0.040, -0.040, -0.040, -0.030, -0.029, -0.029),
        prob = c(0.0, 0.0, 0.0, 0.0, 0.348, 0.020, 0.002, 0.0)
        )

        data_points <- data %>% select(a.data, b.data, years) %>% gather(key = "a_b", value = "data", -years)
        data_lines <- data %>% select(a.mean, b.mean, years) %>% gather(key = "a_b", value = "mean", -years)

        p1 <- ggplot(data_points) +
          geom_point(aes(x = years, y = data, color = factor(a_b))) +
          geom_line(data = data_lines, aes(x = years, y = mean, color = factor(a_b))) +
          theme(legend.position = "none")

         p2 <- ggplot(data) + geom_line(aes(x = years, y = prob))

        grid.arrange(p1, p2)

