date()
## [1] "Wed Sep 12 21:51:21 2012"
Due Date: September 13, 2012
Total Points: 30
1 The following values are the annual number hurricanes that have hit the United States since 1990. Follow instructions and answer questions by typing the appropriate R commands.
0 1 1 1 0 2 2 1 3 3 0 0 1 2 6 6 0 1 3 0 1
a. Enter the data into R. (2)
b. How many years are there? (2)
c. What is the total number of hurricanes over all years? (2)
hCounts = c(0, 1, 1, 1, 0, 2, 2, 1, 3, 3, 0, 0, 1, 2, 6, 6, 0, 1, 3, 0, 1)
hCounts # a.) entered data
## [1] 0 1 1 1 0 2 2 1 3 3 0 0 1 2 6 6 0 1 3 0 1
length(hCounts) # b.) number of years
## [1] 21
sum(hCounts) # c.) number of hurricanes
## [1] 34
2 Answer the following questions by typing the appropriate R commands.
a. Create a vector of numbers starting with 0 and ending with 25. (2)
b. What is the length of this vector? (2)
c. Create a new vector from the original vector by subtracting the mean value over all numbers in the vector. (2)
v = seq(from = 0, to = 25)
v # a.) vector
## [1] 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
## [24] 23 24 25
length(v) # b.) legnth of vector
## [1] 26
mean(v) # mean of vector
## [1] 12.5
v - mean(v) # c.) vector - mean of vector
## [1] -12.5 -11.5 -10.5 -9.5 -8.5 -7.5 -6.5 -5.5 -4.5 -3.5 -2.5
## [12] -1.5 -0.5 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5
## [23] 9.5 10.5 11.5 12.5
3 Suppose you keep track of your mileage each time you fill up. At your last 8 fill-ups the mileage was
65311 65624 65908 66219 66499 66821 67145 67447
a. Enter these numbers into a vector called miles. (2)
b. Use the function diff() to determine the number of miles between fill-ups. (2)
c. What is the maximum, minimum, and mean number of miles between fill-ups? (3)
m = c(65311, 65624, 65908, 66219, 66499, 66821, 67145, 67447)
m # a.) mileage at fill-up
## [1] 65311 65624 65908 66219 66499 66821 67145 67447
m.d1 = diff(m)
m.d1 # b.) mileage between fill-ups
## [1] 313 284 311 280 322 324 302
max(m.d1) # c.1) maximum mileage between fill-ups
## [1] 324
min(m.d1) # c.2) miniumum mileage between fill-ups
## [1] 280
mean(m.d1) # c.3) average mileage between fill-ups
## [1] 305.1
4 Create the following sequences using the seq() and rep() functions as appropriate.
a. “a”, “a”, “a”, “a” (2)
b. The odd numbers in the interval from 1 to 100 (2)
c. 1, 1, 1, 2, 2, 2, 3, 3, 3 (2)
d. 1, 1, 1, 2, 2, 3 (2)
e. 1, 2, 3, 4, 5, 4, 3, 2, 1 (3) Hint: Use the c() function.
rep("a", 4) # a.)
## [1] "a" "a" "a" "a"
seq(1, 100, 2) # b.)
## [1] 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45
## [24] 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91
## [47] 93 95 97 99
c(rep(1, 3), rep(2, 3), rep(3, 3)) # c.)
## [1] 1 1 1 2 2 2 3 3 3
c(rep(1, 3), rep(2, 2), rep(3, 1)) # d.)
## [1] 1 1 1 2 2 3
c(seq(1, 5), seq(4, 1)) # e.)
## [1] 1 2 3 4 5 4 3 2 1