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docs/power_curves.qmd

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+---
+title: "Plots of Power Curves"
+author: "Anthony Steven Dick"
+format:
+  html:
+    code-fold: true
+---
+
+## Load required libraries
+```{r setup, include=TRUE}
+library(ggplot2)
+library(pwr)
+library(patchwork)
+```
+
+## Give range of correlations, range of Cohen's d, and power values
+
+```{r}
+# range of correlations
+r <- seq(.02, .1, .001)
+nr <- length(r)
+
+# range of Cohen's d
+d <- seq(.02, 0.2, length.out = nr)  # Adjusted range for Cohen's d
+nd <- length(d)
+
+# power values
+p <- c(.80, .99)
+np <- length(p)
+```
+
+## Obtain Sample Sizes
+
+```{r}
+# obtain sample sizes for Pearson's correlation coefficient
+samsize_r <- array(numeric(nr*np), dim=c(nr,np))
+for (i in 1:np){
+    for (j in 1:nr){
+        result <- pwr.r.test(n = NULL, r = r[j],
+                             sig.level = .05, power = p[i],
+                             alternative = "two.sided")
+        samsize_r[j,i] <- ceiling(result$n)
+    }
+}
+
+# obtain sample sizes for Cohen's d
+samsize_d <- array(numeric(nd*np), dim=c(nd,np))
+for (i in 1:np){
+    for (j in 1:nd){
+        result <- pwr.t.test(n = NULL, d = d[j],
+                             sig.level = .05, power = p[i],
+                             alternative = "two.sided")
+        samsize_d[j,i] <- ceiling(result$n)
+    }
+}
+```
+
+## Create dataframes for ggplot for Pearson's correlation and Cohen's d
+
+```{r}
+# create dataframe for ggplot for Pearson's correlation coefficient
+df_r <- data.frame(r = rep(r, np), samsize = c(samsize_r[,1], samsize_r[,2]), 
+                   power = rep(p, each = nr), measure = "Pearson's r")
+
+# create dataframe for ggplot for Cohen's d
+df_d <- data.frame(d = rep(d, np), samsize = c(samsize_d[,1], samsize_d[,2]), 
+                   power = rep(p, each = nd), measure = "Cohen's d")
+
+# Rename columns in df_d to match df_r
+names(df_d) <- c("r", "samsize", "power", "measure")
+
+# Combine data frames
+df_combined <- rbind(df_r, df_d)
+```
+
+## Plotting
+
+```{r}
+# Define Hufflepuff colors
+hufflepuff_colors <- c("#FFDD00", "#000000")
+# Plot for Pearson's correlation coefficient
+plot_r <- ggplot(df_r, aes(x = r, y = samsize, color = factor(power))) +
+    geom_line(linewidth = 1) +
+    scale_color_manual(values = hufflepuff_colors) +
+    labs(x = "Correlation Coefficient |r|",
+         y = "Sample Size (n)",
+         color = "Power",
+         title = "Power as a Function of Sample Size for r") +
+    theme_minimal() +
+    geom_hline(yintercept = 11865, linetype = "dashed", color = "black") +
+    scale_y_continuous(breaks = seq(0, 45000, by = 2500)) +
+    scale_x_continuous(breaks = seq(0, 0.1, by = 0.01)) + # Adjusted x-axis breaks
+    theme(legend.position = "none", text = element_text(size = 16))  # Adjust font size here
+```
+
+## More Plotting
+
+```{r}
+# Plot for Cohen's d
+plot_d <- ggplot(df_d, aes(x = r, y = samsize, color = factor(power))) +
+    geom_line(linewidth = 1) +
+    scale_color_manual(values = hufflepuff_colors) +
+    labs(x = "Cohen's d",
+         y = "Sample Size (n)",
+         color = "Power",
+         title = "Power as a Function of Sample Size for Cohen's d") +
+    theme_minimal() +
+    geom_hline(yintercept = 11865, linetype = "dashed", color = "black") +
+    scale_y_continuous(breaks = seq(0, 100000, by = 5000)) +
+    scale_x_continuous(breaks = seq(0, .2, by = 0.05)) + # Adjusted x-axis breaks
+    theme(legend.position = "none", text = element_text(size = 16))  # Adjust font size here
+```
+
+## Combine Plots and Save if Needed
+
+```{r, fig.width=7, fig.height=5}
+
+# Combine plots using patchwork
+combined_plot <- plot_r + plot_d + plot_layout(ncol = 2)
+
+# Add single legend at the bottom
+combined_plot <- combined_plot + theme(legend.position = "right", text = element_text(size = 16))
+
+# Display the combined plot
+print(combined_plot)
+# Save the combined plot to a .tiff file with 600 dpi resolution
+ggsave("combined_plot.tiff", plot = combined_plot, dpi = 600)
+# Save the combined plot to a .eps file
+ggsave("combined_plot.eps", plot = combined_plot, device = "eps")
+
+```