BUSI 240: QUESTIONS AND ANSWERS; LATEST UPDATED VERSION,
ALREADY GRADED A+
Indicate if the following represents independent events. Explain briefly.
The scores you receive on the first midterm, second midterm, and the final exam of a course.
Choose the correct answer below
C : Not independent, because the outcome of one trial does influence or change the outcome of another
In many state lotteries you can choose which numbers to play. Consider a common form in which you
choose 5 numbers. Which of the following strategies can improve your chance of winning? If the
method works, explain why. If not, explain why using appropriate statistics terms.
a) Always play 1, 2, 3, 4, 5.
b) Generate random numbers using a computer or calculator and play those.
PART A : Will always playing 1, 2, 3, 4, 5 improve your chances of winning?
B : No, because each number drawn is equally likely and independent of the others, so this set of
numbers is just as likely as any other in the next drawing.
PART B : Will generating random numbers using a computer or calculator and playing those numbers
improve your chances of winning?
A : No, because each number drawn is equally likely and independent of the others, so this set of
numbers is just as likely as any other in the next drawing.
You and your friend decide to get your cars inspected. You are informed that 67% of cars pass
inspection. If the event of your car's passing is independent of your friend's car
a) What is the probability that your car passes inspection?
b) What is the probability that your car doesn't pass inspection?
c) What is the probability that both of the cars pass?
d) What is the probability that at least one of the two cars passes?
PART A : The probability that your car passes inspection is
= 0.67
PART B : The probability that your car doesn't pass inspection is
= 1 - 0.67
= 0.33
, PART C : The probability that both cars pass inspection is
= (0.67) * (0.67)
= 0.4489
PART D : The probability that at least one car passes inspection is
= 0.67 + 0.67 - 0.4489
= 0.8911
A national survey indicated that 40% of adults conduct their banking online. It also found that 40% are
under the age of 50, and that 10% are under the age of 50 and conduct their banking online.
a) What percentage of adults do not conduct their banking online?
b) What type of probability is the 10% mentioned above?
c) Construct a contingency table showing all joint and marginal probabilities.
d) What is the probability that an individual conducts banking online given that the individual is under
the age of 50?
e) Are Banking online and Age independent? Explain.
PART A : The percentage of adults that do not conduct their banking online is
= 100 - 40
= 60%
PART B : What type of probability is the 10% mentioned above?
= Joint Probability
PART C : Complete the contingency table below.
0.1 0.3 0.4
0.3 0.3 0.6
0.4 0.6 1
PART D : The probability that an individual conducts banking online given that the individual is under the
age of 50 is
= 0.250
PART E : Are Banking online and Age independent? Explain.
D : No, because the conditional probability of banking online for those under 50 is not equal to the
probability of banking online.
ALREADY GRADED A+
Indicate if the following represents independent events. Explain briefly.
The scores you receive on the first midterm, second midterm, and the final exam of a course.
Choose the correct answer below
C : Not independent, because the outcome of one trial does influence or change the outcome of another
In many state lotteries you can choose which numbers to play. Consider a common form in which you
choose 5 numbers. Which of the following strategies can improve your chance of winning? If the
method works, explain why. If not, explain why using appropriate statistics terms.
a) Always play 1, 2, 3, 4, 5.
b) Generate random numbers using a computer or calculator and play those.
PART A : Will always playing 1, 2, 3, 4, 5 improve your chances of winning?
B : No, because each number drawn is equally likely and independent of the others, so this set of
numbers is just as likely as any other in the next drawing.
PART B : Will generating random numbers using a computer or calculator and playing those numbers
improve your chances of winning?
A : No, because each number drawn is equally likely and independent of the others, so this set of
numbers is just as likely as any other in the next drawing.
You and your friend decide to get your cars inspected. You are informed that 67% of cars pass
inspection. If the event of your car's passing is independent of your friend's car
a) What is the probability that your car passes inspection?
b) What is the probability that your car doesn't pass inspection?
c) What is the probability that both of the cars pass?
d) What is the probability that at least one of the two cars passes?
PART A : The probability that your car passes inspection is
= 0.67
PART B : The probability that your car doesn't pass inspection is
= 1 - 0.67
= 0.33
, PART C : The probability that both cars pass inspection is
= (0.67) * (0.67)
= 0.4489
PART D : The probability that at least one car passes inspection is
= 0.67 + 0.67 - 0.4489
= 0.8911
A national survey indicated that 40% of adults conduct their banking online. It also found that 40% are
under the age of 50, and that 10% are under the age of 50 and conduct their banking online.
a) What percentage of adults do not conduct their banking online?
b) What type of probability is the 10% mentioned above?
c) Construct a contingency table showing all joint and marginal probabilities.
d) What is the probability that an individual conducts banking online given that the individual is under
the age of 50?
e) Are Banking online and Age independent? Explain.
PART A : The percentage of adults that do not conduct their banking online is
= 100 - 40
= 60%
PART B : What type of probability is the 10% mentioned above?
= Joint Probability
PART C : Complete the contingency table below.
0.1 0.3 0.4
0.3 0.3 0.6
0.4 0.6 1
PART D : The probability that an individual conducts banking online given that the individual is under the
age of 50 is
= 0.250
PART E : Are Banking online and Age independent? Explain.
D : No, because the conditional probability of banking online for those under 50 is not equal to the
probability of banking online.
