According to data collected for several years, the number of patients who enter the emergency department of a hospital in the Laurentians region each hour follows a Poisson distribution with mean =12 . What is the probability that in 45 minutes the number of patients entering this service is equal to 7?

a. 0,0437.

b. 0,0895.

c. 0,3239.

d. 0,1171.

e. none of these answers.

In an online sales company, historically, it has been observed that 5% of orders are canceled before they are processed. Consider a day when we received 24 online orders. Assuming the orders are independent, what is the probability that at least 22 of these orders will not be canceled before they are processed

a. 0,7768.

b. 0,2232.

c. 0,8840.

d. 0,1160.

e. none of these answers

If is a random variable that follows a binomial distribution (;=0.4) , the value of being unknown. Knowing that the expectation [] is equal to 16, find the value of

a. 20.

b. 40.

c. 80.

d. 160.

e. none of these answers.

A statistics exam consists of 50 multiple-choice questions. For each of these questions, a choice of 5 answers is suggested, of which only one is correct. A correct answer is worth 2 points while a wrong answer is worth 0 points. Consider the case of a student who has not studied for the exam at all and decides to randomly answer all 50 questions. Let X be the numerical mark obtained by this student. What is the variance of X?

a. 8.

b. 16.

c. 32.

d. 64.

e. none of these answers.

A linear regression analysis was performed between the monthly turnover (in thousands of dollars) of a certain company and the monthly expenses incurred in advertising (in dollars). The resulting empirical regression equation is: =120.12+4.12 . Please complete the sentence: According to this equation, we expect that when we spend an additional $1 in advertising in a month, the monthly turnover of this company...

Please choose an answer:

a. increases by $4.12.

b. increases by $124.24.

c. increases by 4120 dollars.

d. increases by $4240.12.

e. None of these answers.

If is a random variable that satisfies the following two equations:

[]=5

[2]=34

What is the coefficient of variation of ?

a. 30%.

b. 40%.

c. 60%.

d. 80%.

e. none of these answers.

Complete the following statement: "If there is a very strong correlation between two variables, then the correlation coefficient must be..."

Please choose an answer:

a. much greater than 1 if it is a positive correlation.

b. much smaller than 1 if it is a negative correlation.

c. much larger than 1 if it is a positive correlation or much smaller than 1 if it is a negative correlation.

d. We cannot complete the statement since the value of the mean and that of the standard deviation are missing.

e. None of these answers.