Multiple Choices: Based Plot: Scatter Plot

Here are 10 multiple-choice exercises on creating scatter plots in R without using the ggplot2 package, focusing on base R plotting functions.

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1. Which function in base R is commonly used to create a scatter plot? ::: {.cell}

plot() scatter() graph() `draw()

2. How do you add a title to a scatter plot in base R? ::: {.cell}

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title() plot(main = "Title") plot(title = "Title") add_title("Title")

3. To change the x-axis label in a scatter plot, which argument would you use? ::: {.cell}

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x_title xlab xlabel x_label

4. How can you change the color of the points in a scatter plot? ::: {.cell}

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col = "color_name" point_col = "color_name" color = "color_name" plot_col = "color_name"

5. Which argument changes the symbol (shape) of the points in a scatter plot? ::: {.cell}

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symbol pch shape type

6. Which code below will create a scatter plot with red points and a title “My Scatter Plot”? ::: {.cell}

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plot(x, y, color = "red", title = "My Scatter Plot") plot(x, y, col = "red", main = "My Scatter Plot") plot(x, y, col = "red", header = "My Scatter Plot") scatter(x, y, col = "red", main = "My Scatter Plot")

7. If you want to add a grid to your scatter plot, which function would you use after plot()? ::: {.cell}

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add.grid() grid() plot_grid() lines()

8. To add a regression line to a scatter plot, which function would you use? ::: {.cell}

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abline() regline() line() addline()

9. Which argument changes the size of the points in a scatter plot? ::: {.cell}

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size pt.size cex scalepoints

10. How can you add labels for individual points on a scatter plot? ::: {.cell}

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text(x, y, labels = c(...)) label(x, y, points = c(...)) point_labels(x, y, labels = c(...)) annotate(x, y, labels = c(...))

11. How can you limit the x-axis range to show only values between 0 and 100 in a scatter plot? ::: {.cell}

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xlim(0, 100) plot(x, y, range = c(0, 100)) plot(x, y, xlim = c(0, 100)) plot(x, y, xlim = c(0, 100))

12. What function would you use to save a scatter plot as a PNG file? ::: {.cell}

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save.plot("plot.png") export("plot.png") png("plot.png") followed by plot(x, y) save_image(“plot.png”)`

13. How would you set the background color of the plotting area to light gray? ::: {.cell}

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plot(bg = "lightgray") plot(x, y, bg = "lightgray") par(bg = "lightgray") before plot(x, y) set_background("lightgray")

14. If you want to overlay a density plot on top of a scatter plot, which function should you use after creating the scatter plot? ::: {.cell}

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density(x, y) points(density(x, y)) lines(density(x)) and lines(density(y), horizontal = TRUE) density_plot(x, y)

15. How do you change the aspect ratio of a scatter plot in base R to ensure that one unit on the x-axis is the same length as one unit on the y-axis? ::: {.cell}

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aspect.ratio = TRUE plot(x, y, asp = 1) plot(x, y, equal.ratio = TRUE) par(aspect = 1)

16. Which function allows you to add points to an existing plot without creating a new plot? ::: {.cell}

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points(x, y) add_points(x, y) plot_more(x, y) new_points(x, y)

17. To add a legend to a scatter plot with different colors for two groups of points, which function should you use? ::: {.cell}

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label() legend() annotate() color_legend()

18. Which argument in the plot() function allows you to specify the type of plot (e.g., lines, points, both)? ::: {.cell}

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type plot_type pt_type chart_type

19. What command can be used to add a smooth curve to a scatter plot by fitting a loess (local regression) line? ::: {.cell}

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smooth(x, y) loess.smooth(x, y) scatter.smooth(x, y) scatter.smooth(x, y)

20. If you want to create a scatter plot in which the point size represents a third variable (e.g., z), which argument would you use? ::: {.cell}

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cex = z size = z pch = z cex = z / max(z)

21. How can you rotate the y-axis label in a scatter plot to make it horizontal? ::: {.cell}

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cex = z size = z pch = z cex = z / max(z)

22. To remove the axes entirely from a scatter plot, which argument would you use? ::: {.cell}

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axes = FALSE axis = NULL show_axes = FALSE plot_axes = FALSE

23. When you want to customize tick marks on the x-axis (e.g., add ticks at specific values), which function should you use after plot()? ::: {.cell}

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add_ticks(x, values = c(...)) axis(1, at = c(...)) set_ticks(1, values = c(...)) plot_ticks(1, values = c(...))

24. How can you label specific points (e.g., outliers) with their coordinates on a scatter plot? ::: {.cell}

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add_text() text(x, y, labels = paste("(", x, ",", y, ")")) annotate_points(x, y, labels = paste("(", x, ",", y, ")")) point_label(x, y, coords = TRUE)

25. Which function would you use to add custom axis labels on an existing scatter plot? ::: {.cell}

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label_axis() set_labels() mtext() axis_labels()

26. How do you adjust the margin space around a plot in base R? ::: {.cell}

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par(mar = c(...)) plot(margin = c(...)) set_margins = c(...) plot(mar = c(...))

27. If you want to add a border around the entire plot area, which function should you use? ::: {.cell}

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border() frame() box() outline()

28. How can you plot a scatter plot with a logarithmic scale on both axes? ::: {.cell}

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plot(x, y, scale = "log") plot(x, y, log = "xy") plot(x, y, log_scale = TRUE) plot(x, y, log = TRUE)

29. Which argument in the plot() function can be used to specify custom limits for both x and y axes simultaneously? ::: {.cell}

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xlim = c(...) and ylim = c(...) range = list(...) limits = c(xmin, xmax, ymin, ymax) xylim = c(...)

30. To add multiple scatter plots on the same graphic device (in a grid layout), which function should you use before plot()? ::: {.cell}

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split.screen() layout() par(mfrow = c(...)) screen.grid()

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