Problems

Hone your R skills by doing problems.

The assignment is due next Wednesday and you are encouraged to work in group and to hand in a single copy for the group.

1 Use R to produce a bar graph from this table:


Country Freq
India 5
China 7
Russia 2
Nigeria 5
Iran 3
Other 4
Total 26

2 Data manipulation. Load the data ‘tornado.csv’.


Tornado Data

2.1 How many tornadoes occurred in AL (Alabama) and AR (Arkansas).

2.2 How many tornadoes occurred in TX (Texas) before 2010.

2.3 Return the ‘mo’ (month), ‘yr’ (year), and ‘f’ (F-scale) for all tornadoes that occurred in DE (Delaware).

2.4 Arrange the tornadoes by date and time. What state had the most recent tornado?

2.5 Get the count of tornadoes by year.

2.6 Add a new column, num_f, by transforming f into a variable of class numeric instead of factor.