In a sequence of independent flips of a fair coin, let N denote
the number of...
In a sequence of independent flips of a fair coin, let N denote
the number of flips until there is a run of three consecutive
heads. Find P(N ≤ 8). (Should write out transition matrix.)
In
a sequence of independent flips of a fair coin thwr comes up heads
with probability 0.6, what is the probability that there is a run
of three consecutive heads within the first 10 flips?
Show a Markov chain that counts the number of consecutive
heads attained.
A fair coin is flipped until a head appears. Let the number of
flips required be denoted N (the head appears on the ,\1th flip).
Assu1ne the flips are independent. Let the o utcon1es be denoted by
k fork= 1,2,3, . ... The event {N = k} 1neans exactly k flips are
required. The event {,v;;, k} n1eans at least k flips are
required.
a. How n1any o utcon1es are there?
b. What is Pr[N = k] (i.e., the probability...
Flip a fair coin 4 times. Let ? and ? denote the number of heads
and tails correspondingly.
(a) What is the distribution of ?? What is the distribution of ?
?
(b) Find the joint PMF. Are ? and ? independent?
(c) Calculate ?(? ?) and ?(X≠?)(d) Calculate C??(?, ? ) and
C???(?, ? )
A fair coin is tossed four times. Let X denote the number of
heads occurring and let Y denote the longest string of heads
occurring. (i) determine the joint distribution of X and Y (ii)
Find Cov(X,Y) and ρ(X,Y).
Q7 A fair coin is tossed three times independently: let X denote
the number of heads on the first toss (i.e., X = 1 if the first
toss is a head; otherwise X = 0) and Y denote the total number of
heads.
Hint: first figure out the possible values of X and Y , then
complete the table cell by cell.
Marginalize the joint probability mass function of X and Y in
the previous qusetion to get marginal PMF’s.
You roll two fair four-sided dies and then flip a fair coin. The
number of flips is the total of the roll.
a. Find the expected value of the number of heads observed.
b. Find the variance of the number of heads observed.
An
honest coin is tossed n=3600 times. Let the random variable Y
denote the number of tails tossed. Use the 68-95-99.7 rule to
determine the chances of the outcomes. (A) Estimate the chances
that Y will fall somewhere between 1800 and 1860. (B) Estimate the
chances that Y will fall somewhere between 1860 and 1890.
Let τ (n) denote the number of positive divisors of n and σ(n)
denote the sum of the positive divisors of n (as in the notes).
(a) Evaluate τ (1500) and σ(8!).
(b) Verify that τ (n) = τ (n + 1) = τ (n + 2) = τ (n + 3) holds
for n = 3655 and 4503.
(c) When n = 14, n = 206 and n = 957, show that σ(n) = σ(n +
1).
Let discrete random variable X be the number of flips of a
biased coin required to get tails, where P(tails) = 1/3 .
a) Calculate the probability for every value of X from 1 to
10.
b) Sketch a plot of the p.m.f. of X for the first 10 flips.
c) Sketch a plot the c.d.f. of X for the first 10 flips.
A fair coin is flipped six times. The outcomes of the coin flips
form a palindrome if the sequence of T’s and H’s reads the same
forwards and backwards, e.g. THTTHT.
Let A denote the event that the first, second and fourth flips
are all ‘T’. Let Z denote the event that the six flips form a
palindrome.
(a) Is A independent of Z?
(b) Is A independent of Z?
(c) A fair coin flipped six times and a certain...