BSTAT 2305 FINAL questions n answers
graded A+ passed
The following histogram represents the number of pages in each book within a collection. What
is the frequency of books containing at least 250 but fewer than 400 pages? - correct answer
✔✔11
Add the frequencies, 7, 3, and 1, for the classes 250 up to 300, 300 up to 350, and 350 up to
400.
The accompanying relative frequency distribution represents the last year car sales for the sales
force at Kelly's Mega Used Car Center.
Car Sales - Relative Frequency
35 up to 45 - 0.07
45 up to 55 - 0.15
55 up to 65 - 0.31
65 up to 75 - 0.22
75 up to 85 - 0.25
If Kelly's employs 100 salespeople, how many of these salespeople have sold at least 65 cars in
the last year? - correct answer ✔✔47
(0.22 + 0.25)100 = 47 employees.
The number of cars sold by a car salesperson during each of the last 25 weeks is the following:
,Number Sold - Frequency
0 - 10
1 - 10
2-5
What is the probability that the salesperson will sell one car during a week? - correct answer
✔✔0.40
P(X = 1) = 10/25 = 0.40
Consider the following discrete probability distribution.
x - P(X = x)
-10 - 0.35
0 - 0.10
10 - 0.15
20 - 0.40
What is the probability that X is less than 5? - correct answer ✔✔0.45
P(X < 5) = P(X = −10) + P(X = 0) = 0.35 + 0.10 = 0.45
The director of graduate admissions is analyzing the relationship between scores in the GRE and
student performance in graduate school, as measured by a student's GPA. The table below
shows a sample of 10 students. - correct answer ✔✔The correlation between GRE and GPA is
positive and strong.
,=CORREL(<GRE data>,<GPA data>) = 0.894
There are 30 Major League Baseball teams in the National League. Five of these teams will make
the playoffs at the end of the season. The number of unique groups of teams that can make the
playoffs is ______. - correct answer ✔✔142,506
In Excel, the function used is =COMBIN(30,5) = 142,506
The number of homes sold by a realtor during a month has the following probability
distribution:
Number Sold - Probability
0 - 0.20
1 - 0.40
2 - 0.40
What is the standard deviation of the number of homes sold by the realtor during a month? -
correct answer ✔✔0.75
The standard deviation of the discrete random variable X is calculated as SD(X)=σ=√σ^2. The
variance of the discrete random variable X is calculated as Var(X) = σ^2 = ∑(xi − μ)^2 P(X = xi).
E(X) = 0 × 0.20 + 1 × 0.40 + 2 × 0.40 = 1.2
Var(X) = (0 − 1.2)^2 × 0.20 + (1 − 1.2)^2 × 0.40 + (2 − 1.2)2 × 0.40 = 0.56
SD(X) = √0.56 = 0.75
, A company is bidding on two projects, A and B. The probability that the company wins project A
is 0.40 and the probability that the company wins project B is 0.25. Winning project A and
winning project B are independent events. What is the probability that the company does not
win either project? - correct answer ✔✔0.45
The addition rule is calculated as P(A∪B) = P(A) + P(B − P(A∩B). A complement rule is P(A) = 1 −
P(A^c).
P(A∪B) = 0.40 + 0.25 − 0.1 = 0.55
Neither = 1 − P(A∪B) = 1 − 0.55 = 0.45
An investor bought common stock of Blackstone Company on several occasions at the following
prices.The following frequency distribution represents the number of shares and its price per
share.
Number of Shares - Price per Share
100 - $40
200 - $32
400 - $26
The average price per share at which the investor bought these shares of common stock was the
closest to __________. - correct answer ✔✔$29.71
x = (100 × 34 + 200 × 30 + 400 × 28)/(100 + 200 + 400) = 100/700 × 34 + 200/700 × 30 + 400/700
× 28 = 29.43.
5! is equal to _______. - correct answer ✔✔5 × 4 × 3 × 2 × 1
The annual returns (in percent) for a sample of stocks in the technology industry over the past
year are as follows:
graded A+ passed
The following histogram represents the number of pages in each book within a collection. What
is the frequency of books containing at least 250 but fewer than 400 pages? - correct answer
✔✔11
Add the frequencies, 7, 3, and 1, for the classes 250 up to 300, 300 up to 350, and 350 up to
400.
The accompanying relative frequency distribution represents the last year car sales for the sales
force at Kelly's Mega Used Car Center.
Car Sales - Relative Frequency
35 up to 45 - 0.07
45 up to 55 - 0.15
55 up to 65 - 0.31
65 up to 75 - 0.22
75 up to 85 - 0.25
If Kelly's employs 100 salespeople, how many of these salespeople have sold at least 65 cars in
the last year? - correct answer ✔✔47
(0.22 + 0.25)100 = 47 employees.
The number of cars sold by a car salesperson during each of the last 25 weeks is the following:
,Number Sold - Frequency
0 - 10
1 - 10
2-5
What is the probability that the salesperson will sell one car during a week? - correct answer
✔✔0.40
P(X = 1) = 10/25 = 0.40
Consider the following discrete probability distribution.
x - P(X = x)
-10 - 0.35
0 - 0.10
10 - 0.15
20 - 0.40
What is the probability that X is less than 5? - correct answer ✔✔0.45
P(X < 5) = P(X = −10) + P(X = 0) = 0.35 + 0.10 = 0.45
The director of graduate admissions is analyzing the relationship between scores in the GRE and
student performance in graduate school, as measured by a student's GPA. The table below
shows a sample of 10 students. - correct answer ✔✔The correlation between GRE and GPA is
positive and strong.
,=CORREL(<GRE data>,<GPA data>) = 0.894
There are 30 Major League Baseball teams in the National League. Five of these teams will make
the playoffs at the end of the season. The number of unique groups of teams that can make the
playoffs is ______. - correct answer ✔✔142,506
In Excel, the function used is =COMBIN(30,5) = 142,506
The number of homes sold by a realtor during a month has the following probability
distribution:
Number Sold - Probability
0 - 0.20
1 - 0.40
2 - 0.40
What is the standard deviation of the number of homes sold by the realtor during a month? -
correct answer ✔✔0.75
The standard deviation of the discrete random variable X is calculated as SD(X)=σ=√σ^2. The
variance of the discrete random variable X is calculated as Var(X) = σ^2 = ∑(xi − μ)^2 P(X = xi).
E(X) = 0 × 0.20 + 1 × 0.40 + 2 × 0.40 = 1.2
Var(X) = (0 − 1.2)^2 × 0.20 + (1 − 1.2)^2 × 0.40 + (2 − 1.2)2 × 0.40 = 0.56
SD(X) = √0.56 = 0.75
, A company is bidding on two projects, A and B. The probability that the company wins project A
is 0.40 and the probability that the company wins project B is 0.25. Winning project A and
winning project B are independent events. What is the probability that the company does not
win either project? - correct answer ✔✔0.45
The addition rule is calculated as P(A∪B) = P(A) + P(B − P(A∩B). A complement rule is P(A) = 1 −
P(A^c).
P(A∪B) = 0.40 + 0.25 − 0.1 = 0.55
Neither = 1 − P(A∪B) = 1 − 0.55 = 0.45
An investor bought common stock of Blackstone Company on several occasions at the following
prices.The following frequency distribution represents the number of shares and its price per
share.
Number of Shares - Price per Share
100 - $40
200 - $32
400 - $26
The average price per share at which the investor bought these shares of common stock was the
closest to __________. - correct answer ✔✔$29.71
x = (100 × 34 + 200 × 30 + 400 × 28)/(100 + 200 + 400) = 100/700 × 34 + 200/700 × 30 + 400/700
× 28 = 29.43.
5! is equal to _______. - correct answer ✔✔5 × 4 × 3 × 2 × 1
The annual returns (in percent) for a sample of stocks in the technology industry over the past
year are as follows:
