QUESTION 1 (Data Exploration)
Data exploration starts with inspecting the dimensionality and structure of data, followed by descriptive statistics and various charts like pie charts, bar charts, histograms, and box plots. Exploration of multiple variables includes grouped distribution, grouped boxplots, scattered plots, and pairs plots. Advanced exploration presents some fancy visualization using 3D plots, level plots, contour plots, interactive plots, and parallel coordinates. Refer to the Iris data and explore it by answering the following questions:
i. Check the dimension of data and name the variables (from left to right): Sepal.Length, Sepal.Width, Petal.Length, Petal.Width, Species.
ii. Explore Individual variables.
a. Choose Sepal.Length. Provide descriptive statistics (summary) which returns the minimum, maximum, mean, median, standard deviation, first quartile, third quartile, interquartile range, skewness, and kurtosis. Interpret the output based on location measure (mean), dispersion measure (standard deviation), and shape measure (skewness).
b. Plot the histogram. Does the distribution of Sepal.Length appear symmetrical?
c. Plot a pie chart for Species.
iii. Explore Multiple variables. Consider Sepal.Length, Sepal.Width, Petal.Length, Petal.Width.
a. Calculate covariance and correlation.
b. Plot a side-by-side box plot and whiskers, which shows the median, first and third quartiles of a distribution, and outliers (if present). Compare the distribution of the four variables and observe any outliers.
c. Plot a matrix of scatter plots. Explain the correlation of variables.
iv. For advanced exploration, choose Sepal.Length, Sepal.Width, Petal.Width. Produce a 3D scatterplot. Explain the plot.