Q1:

print(matrix(1:9,nrow=3))

Q2:

print(c(3/36,2/36,2/36,2/36))

Q3:

# use (3.36), with g(t) = [(t -mu) / sigma]^3, taking mu and sigma from 
# (3.78) and (3.79)
skInd <- function(w)
{
   mu <- w
   sigma <- sqrt(w*(1-w))
   tmp <- w * ( (1-mu)/sigma )^3
   tmp + (1-w) * ( (0-mu)/sigma )^3
}

print(skInd(0.25))  # about 1.15

Q4:

varx <- function(pvec)  # n inferred, no need for a parameter n
{
   sum(pvec*(1-pvec))
}

print(varx(c(0.25,0.45,0.30)))  # about 0.645