Homework 03 is ready for grading

[yanchaoluo]

@vincenzocoia @gvdr @ksedivyhaley @JoeyBernhardt @mynamedaike @pgonzaleze @derekcho

• Homework3 Markdown
• Homework3 file

SHA: bfc909f7983c0b8aa99e7c389010af459c957903

Thanks.

[wswade2]

Hi Yanchao,

You did a very thorough job with this homework and completed 5 tasks when only 3 were required. I have not yet learned to use the summarise () function to calculate min/max, so that code was informative for me. Your code also taught me how to use the xtable () command. I also liked the variety of graphs you used. I was not previously aware of the possibility of highlighting outliers within the theme command, which will be extremely useful in the future.

I would note however that there are several typos in your code. I also think that better labels for your graphs would improve their interpretability and aesthetic appeal. You did interpret your code at points but I think more commentary would have been useful. I'm not sure how to correct the code you asked for help for at the bottom of your assignment. But that is a good idea that I might use in the future, I'm sure you will learn very quickly that way.

Overall, my evaluation of your assignment is: check-plus.

Wade

[bcahn7]

Hello @yanchaoluo , Here are some comments on your hw03. Hope it helps!

• Your README.md file is well-organized so I can easily find what you did in hw03. This is just a trivial one but the links to .md file and .Rmd file are switched.
• It was good to know about xtable.
• You adjusted the scale of y-axis in the time-series plot for gdpPercap in each continent using facet_wrap(~continent, scales="free_y"). This makes the plot for each continent more readable. In addition, you indicated maximum and minimum values in each continent using different color and shape. It would be better to use different color for the minimum value to distinguish itself from points nearby even though the minimum point is in different shape and size (I think you wanted to show different ways of distinguish the point though). I knew the functions but I haven't tried in this way. Those will be very useful in the future.
• You calculated weighted mean. Also, you could try to calculate trimmed mean, which is the mean where the fraction of observations to be trimmed from each end of values before the mean is computed. For example, mean(lifeExp, trim=0.1). trim=0.1 means cutting off 10% of each end of values.
• In the population-Change_lifeExp plot for the Asian countries, it was good to see the whole countries first and analyze the two biggest countries' trend. It also would be meaningful if you could analyze the remaining countries, taking out China and India as those two countries make it hard to interpret the trend for the remaining countries.

Overall, I think you did a great job! I learned a new function xtable() and new ways to visualize the data. Well done!

[winniewytse]

Hi @yanchaoluo, great job on your homework 03 👍 Here are a few things I like about it,

1. Great attempts on customizing themes of many of your graphs. They look pretty and refreshing.
2. Your graphs for finding the maximum and minimum gdp per capita are comprehensive. The scatterplot shows the spread of the data of each continent, and the graphs per continent with a regression line shows the trend of the data. You are creative to have a blue dot and a triangle representing the maximum and minimum points among all data points in the final graph. Nice try on that.
3. The graph of life expectancy vs year is just beautiful! I like all regression lines of each continent with different colours. That helps readers know and compare the change in life expectancy across years. Great job.
4. Good try in looking into the population growth of China and India which are pretty much the outliers of the population graph that contains all Asian countries.

Recommendation:

1. I would recommend filtering the minimum and maximum points for each continent before making a graph in task 1, or simply making a boxplot for each continent would be simpler to read.

[ksedivyhaley]

@winnietse1018, this week you were assigned to peer review hannahdxz and estennw.

At least three tasks: Yes (5) A table and figure for each task: Yes Comments on tables/figures: Yes Reflections on Process: Yes Bonus (side-by-side layout, table formatting): xtable, attempted layout

Comments:

• Nice use of colour to pick out outliers.
• To fix your plot graphing both the mean and the weighted mean, use geom_line(aes(y=life_mean)) instead of geom_line(aes(life_mean)). If you don't specify that the mean is meant to be plotted on the y axis, the aes() command thinks it's supposed to be the x-axis (since that's the first argument). When in doubt, specify which arguments you are setting within the function!
• The problem with diff has to do with how the ifelse statement reads the result of the diff() function – notice how the incorrect code uses the same numbers but skips the 1.531 right after the first 0?
• For stargazer I suggest slack or office hours.
• To improve, work on graph readability - eg pay attention to titles and axis labels, adjust the task 5 plot so you can see the smaller population countries, and make the minimum more visible in task 1.

Your mark will be distributed later. If you would like more feedback, please feel free to message me on slack.