4. For question 4, you will use an imported data. Run the following R code (in blue) and use the thdcta data set to answer the questions. R codes: hwl _data = read.csv( \"https: / f raw. githubltsercontentcom / hgweonZ / 933859 / master / thdatal .csv\" ) The imported data set contains 100 observations with 2 variables: x1 and x2. Include your R codes and output for the following questions. (a) Count the number of observations whose X] are greater than 6. (1 pt) (b) Count the number of observations Whose x1 are greater than 6 and X2 equal to H. (1 pt) (c) Consider a subset A that contains all observations with x2 = H. Compute the mean, median and standard deviation of the x1 values in subset A. [1 pt) ((1) The sample mean of x1 is 4.435. Can we argue that the true mean of 2:1 differs from 4? Conduct a ttest at signicance level 0: = 0.05. Give the test statistic [tvalue), pvalue and your conclusion. (1 pt) (9) Consider the statement: \"Given that x2 equals to H1 the true mean of x1 is larger than 4.\" Is this statement convincing? Use a t-test (a : 0.05) to support your answer. {2 pt)