Question 5.11 The increase or decrease in the price of a stock between the beginning and the end of

a trading day is assumed to be an equally likely random event. What is the probability

that a stock will show an increase in its closing price on five consecutive days? Question 5.13

A student is taking a multiple-choice exam in which each question has four choices.

Assume that the student has no knowledge of the correct answers to any of the

questions. She has decided on a strategy in which she will place four balls (marked A,

B, C and D) into a box. The marking on the ball will determine her answer to the

question. There are ﬁve multiple choice questions on the exam. What is the probability

that she will get: a. Five questions correct?

b. At least four questions correct?

c. No questions correct?

d. No more than two questions correct? Question 5.21|

Assume that the number of new visitors to a website in one minute is distributed as a

Poisson variable. The mean number of new visitors to the website is 4.0 per minute.

What is the probability that in any given minute:

a Zero new visitors will arrive at the website?

Exactly one new visitor will arrive at the website? b.

c. Two or more new visitors will arrive at the website?

cl. Fewer than three new visitors will arrive at the website?