A letter is chosen uniformly at random from {A, B, . . . , Z}. If that letter is one of the vowels (i.e. A, E, I, O or U) then a second letter is chosen uniformly at random from {A, B, . . . , Z}. Let L be the number of letters chosen and let V be the number of vowels chosen.
(i) What is the expected value of L?
(ii) What is the expected value of V?
(iii) Are L and V independent?
(iv) What is the probability that two letters are chosen and that they are equal?
(v) What is the probability that at least one U is chosen?
A letter is chosen uniformly at random from {A, B, . . . , Z}. If...
[2] [3] (5) (a) A soccer squad contains 3 goalkeepers, 7 defenders, 9 midfielders and 4 forwards. (i) In how many ways can a team of 1 goalkeeper, 4 defenders, 4 midfielders, and 2 attackers be chosen from this squad? (ii) Two of the defenders refuse to play together. In how many ways can a team be chosen that contains at most one of these two defenders? (b) Let p and q be real numbers. A random variable X has...
Exercise 2.38. We choose one of the words in the following sentence uniformly at random and then choose one of the letters of that word, again uniformly at random: SOME DOGS ARE BROWN (a) Find the probability that the chosen letter is R. (b) Let X denote the length of the chosen word. Determine the probability mass function of X. (c) For each possible value k of X determine the conditional probability P(X k|X 3) Hint. The decomposition idea works...
2. You randomly choose a letter from (A, B, C, D, E and a friend randomly chooses a letter from fa, b, c, d, e to create a pair of 2 letters with 1 upper case letter followed by 1 lower case letter. (Note: in the English alphabet, the vowels are A, E, I, O, U.) a) Write out the sample space for this experiment. (For example one outcome in the sample space is: Ac; another is Bb.) For parts...
A hacker has programmed their computer to generate, uniformly at random, an eight-character password, with each character being either one of 26 lower-case letters (a-z), one of 26 upper-case letters (A-Z) or one of 10 integers (0-9). The hacker wants to infiltrate a website that has 2 million users. Assume, for simplicity, that each user is required to use a unique password. i. What is the expected number of attempts before the hacker successfully generates a user password? ii. What...
Let a random variable X be uniformly distributed between −1 and 2. Let another random variable Y be normally distributed with mean −8 and standard deviation 3. Also, let V = 22+X and W = 13+X −2Y . (a) Is X discrete or continuous? Draw and explain. (b) Is Y discrete or continuous? Draw and explain. (c) Find the following probabilities. (i) The probability that X is less than 2. (ii) P(X > 0) (iii) P(Y > −11) (iv) P...
can you try these I do not know if they are correct (from e-h mainly) please check the others if you have the time to The English alphabet has 26 letters. There are 6 vowels. (a, e, i, o, u, and sometimes y). Suppose we randomly select 8 letters from the alphabet without replacement. Let X = the number of vowels chosen (including y as a vowel). a. How many possible ways are there to select the 8 out of...
1) (a) (14 pts.) Consider the experiment in which a number is chosen uniformly in (1; 2; : : : ; 10). Let event A be the number is divisible by 3, and event B be the number is (strictly-) greater than 5. (i) Write the sample space S for the aforementioned experiment and express events A and B as subsets of S. (ii) Are A and B mutually exclusive? Prove. (iii) Are A and B statistically independent? Prove.
Problem 3.4 (10 points) Consider this game of chance with a monetary payoff. First, a real number is chosen uniformly at random from the interval [0,10]. Next, an integer X is chosen according to the Poisson distribution with parameter U. The player receives a reward of SX What would be the fair price charged for playing this game? That is, how much should it cost to play so that expected net gain is zero? Problem 3.4 (10 points) Consider this...
Let X1, X2, ..., Xn be a random sample of size 5 from a normal population with mean 0 and variance 1. Let X6 be another independent observation from the same population. What is the distribution of these random variables? i) 3X5 – X6+1 ii) W, = - X? iii) Uz = _1(X; - X5)2 iv) Wą +xz v) U. + x vi) V5Xe vii) 2X
3. A computer chooses 100 independent random numbers, each uniformly from the set of integers between 1 and 200. What is the expected value of: (a) The number of the chosen numbers which are multiples of 10