©THEBRIGHT EXAM SOLUTIONS
11/06/2024 10:41 AM
Sta midterm ch4 Exam Questions And
Answers 100% Pass
If A denotes some event, what does A bar(complement) denote? If P(A)=0.005, what is the
value of P(A bar)? If P(A)=0.005, is A bar(complement) unlikely? - answer✔Event A
bar(complement) denotes the complement of event A, meaning that A bar(complement)
consists of all outcomes in which event A does not occur.
P(A bar) = .995
It is not unlikely
How do you get the probability of the complement of A or P(A bar(complement))? - answer✔1 -
P(A)
Assume that 900 births are randomly selected and exactly 446 of the births are girls. Use
subjective judgment to determine whether the given outcome is unlikely, and also determine
whether it is unusual in the sense that the result is far from what is typically expected.
a) Determine whether exactly 446 girls out of 900 randomly selected births is unlikely.
b) Determine whether exactly 446 girls out of 900 randomly selected births is unusual. -
answer✔a) It is unlikely because the probability of this particular outcome is very small,
considering all of the other possible outcomes.
b) It is not unusual because 446 is about the number of girls expected.
explanation: the specific number "446" is unlikely, but 446 is not unusual because the
probability of having a girl is 0.5, and half of 900 is 450.
In a test of a gender-selection technique, results consisted of 274 baby girls and 5 baby boys.
Based on this result, what is the probability of a girl born to a couple using this technique? Does
it appear that the technique is effective in increasing the likelihood that a baby will be a girl? -
answer✔The probability of a girl born is 274/279.
, ©THEBRIGHT EXAM SOLUTIONS
11/06/2024 10:41 AM
Yes it is effective
In a genetics experiment on peas, one sample of offspring contained 355 green peas and 132
yellow peas. Based on those results, estimate the probability of getting an offspring pea that is
green. Is the result reasonably close to the value of 3/4 that was expected? - answer✔The
probability of getting an offspring pea that is green is 355/487. explanation: 355 + 132 = 487,
then 355/487 = .729
Yes, 0.729 is close to 3/4.
To the right are the outcomes that are possible when a couple has three children. Refer to that
list, and find the probability of each event.
boy-boy-boy
boy-boy-girl
boy-girl-boy
boy-girl-girl
girl-boy-boy
girl-boy-girl
girl-girl-boy
girl-girl-girl
a. Among three children, there is exactly 1 boy.
b. Among three children, there are exactly 0 boys.
c. Among three children, there are exactly 2 boys. - answer✔a) 3/8
b) 1/8
c) 3/8
If a couple were planning to have three children, the sample space summarizing the gender
outcomes would be: bbb, bbg, bgb, bgg, gbb, gbg, ggb, ggg.
a. Construct a similar sample space for the possible eye color outcomes (using b for blue-eyed
and g for green-eyed) of two children.
b. Assuming that the outcomes listed in part (a) were equally likely, find the probability of
getting two blue-eyed children.
11/06/2024 10:41 AM
Sta midterm ch4 Exam Questions And
Answers 100% Pass
If A denotes some event, what does A bar(complement) denote? If P(A)=0.005, what is the
value of P(A bar)? If P(A)=0.005, is A bar(complement) unlikely? - answer✔Event A
bar(complement) denotes the complement of event A, meaning that A bar(complement)
consists of all outcomes in which event A does not occur.
P(A bar) = .995
It is not unlikely
How do you get the probability of the complement of A or P(A bar(complement))? - answer✔1 -
P(A)
Assume that 900 births are randomly selected and exactly 446 of the births are girls. Use
subjective judgment to determine whether the given outcome is unlikely, and also determine
whether it is unusual in the sense that the result is far from what is typically expected.
a) Determine whether exactly 446 girls out of 900 randomly selected births is unlikely.
b) Determine whether exactly 446 girls out of 900 randomly selected births is unusual. -
answer✔a) It is unlikely because the probability of this particular outcome is very small,
considering all of the other possible outcomes.
b) It is not unusual because 446 is about the number of girls expected.
explanation: the specific number "446" is unlikely, but 446 is not unusual because the
probability of having a girl is 0.5, and half of 900 is 450.
In a test of a gender-selection technique, results consisted of 274 baby girls and 5 baby boys.
Based on this result, what is the probability of a girl born to a couple using this technique? Does
it appear that the technique is effective in increasing the likelihood that a baby will be a girl? -
answer✔The probability of a girl born is 274/279.
, ©THEBRIGHT EXAM SOLUTIONS
11/06/2024 10:41 AM
Yes it is effective
In a genetics experiment on peas, one sample of offspring contained 355 green peas and 132
yellow peas. Based on those results, estimate the probability of getting an offspring pea that is
green. Is the result reasonably close to the value of 3/4 that was expected? - answer✔The
probability of getting an offspring pea that is green is 355/487. explanation: 355 + 132 = 487,
then 355/487 = .729
Yes, 0.729 is close to 3/4.
To the right are the outcomes that are possible when a couple has three children. Refer to that
list, and find the probability of each event.
boy-boy-boy
boy-boy-girl
boy-girl-boy
boy-girl-girl
girl-boy-boy
girl-boy-girl
girl-girl-boy
girl-girl-girl
a. Among three children, there is exactly 1 boy.
b. Among three children, there are exactly 0 boys.
c. Among three children, there are exactly 2 boys. - answer✔a) 3/8
b) 1/8
c) 3/8
If a couple were planning to have three children, the sample space summarizing the gender
outcomes would be: bbb, bbg, bgb, bgg, gbb, gbg, ggb, ggg.
a. Construct a similar sample space for the possible eye color outcomes (using b for blue-eyed
and g for green-eyed) of two children.
b. Assuming that the outcomes listed in part (a) were equally likely, find the probability of
getting two blue-eyed children.
