Create a variable called x and assign the following numeric values: 5, 8, 13, 4, 21, 30, 2, 11.
Extract the fifth element of x.
Extract the first two and the last two elements of x.
Extract all elements of x which are greater than 20.
Create a subset of x containing values smaller than 5 or greater than or equal to 13.
Load and call up the built-in data set OrchardSprays.
Create a new data frame called dat that only contains the decrease and the treatment variables.
Form a subset of dat that only contains treatment D.
Form a subset of dat that only contains treatment D and observations where the response decrease was larger than 30.
Form a subset of dat that only contains treatment D and observations where the response decrease was between 30 and 50.