Math

Question 1

sin,cos,tan,asin,acos,atan,atan2,log,log10,exp max(x) min(x) sum(x) mean(x) median(x) rank(x) var(x) sd(x) cor(x) var(x, y) cor(x, y)

Answer 1

simple math functions

Question 2

range(x)

Answer 2

id. then c(min(x), max(x))

Question 3

diff(x)

Answer 3

lagged and iterated differences of vector x

Question 4

prod(x)

Answer 4

product of the elements of x

Question 5

quantile(x,probs=)

Answer 5

sample quantiles corresponding to the given prob-

abilities (defaults to 0,.25,.5,.75,1)

Question 6

weighted.mean(x, w)

Answer 6

mean of x with weights w

Question 7

round(x, n)

Answer 7

round(x, n)

Question 8

log(x, base)

Answer 8

computes the logarithm of x with base base

Question 9

scale(x)

Answer 9

if x is a matrix, centers and reduces the data; to center only use
the option center=FALSE, to reduce only scale=FALSE (by default
center=TRUE, scale=TRUE)

Question 10

pmin(x,y,…)

Answer 10

a vector which ith element is the minimum of x[i],

y[i], . . .

Question 11

pmax(x,y,…)

Answer 11

d. for the maximum

Question 12

cumsum(x)

Answer 12

a vector which ith element is the sum from x[1] to x[i]

Question 13

cumprod(x)

Answer 13

d. for the product

Question 14

cummin(x)

Answer 14

id. for the minimum

Question 15

cummax(x)

Answer 15

d. for the maximum

Question 16

union(x,y), intersect(x,y), setdiff(x,y), setequal(x,y),

is.element(el,set)

Answer 16

“set” functions

Question 17

Mod(x)

Answer 17

modulus; abs(x) is the same