PBSI 245 - Exam 3 questions n
answers graded A+ passed
Frequentism - correct answer ✔✔What would happen if we did this many times?
Outcomes in the short run are ruled by chance.
But certain patterns emerge if events are repeated over and over.
Based on very many repetitions on which that outcome occurs
Truths about probability - correct answer ✔✔- chance behavior is unpredictable in the short run
- but has regular and predictable pattern in the long run
Random - correct answer ✔✔individual outcomes are uncertain, but regular distribution of
outcomes in large number of repetitions
Probability - correct answer ✔✔- a number between 0 and 1
- describes the proportion of times the outcome would occur in a very long series of repetitions
Myth of short-run regularity - correct answer ✔✔Randomness: only regular in long-run
Misleading human intuition: "I'm due for a win!"
When they don't seem to be: we look for some explanation other than chance variance
, Which of these is most probable? (HTHTTH, TTTHHH, TTTTTT) - correct answer ✔✔All equal!
(coins have to memory)
Myth of law of averages - correct answer ✔✔intuition that tells us that future outcomes must
make up for an imbalance of results
REALITY:
- there is no "must"
- nothing is forcing a coin to go one way or another on any trial (no memory)
- It is an independent event
What is the law of averages? - correct answer ✔✔a fallacy based on the assumption that events
of one kind are always balanced by events of another kind
Law of large numbers - correct answer ✔✔in a large number of "independent" repetitions of a
random phenomenon (like tossing a coin), averages are likely to become more stable as the
number of trials increases, BUT sums/counts are likely to become more variable
A probability of _______ distribution is a statistic. - correct answer ✔✔sampling
Probability that A or B happens: - correct answer ✔✔P(A) + P(B)
Probability rule A - correct answer ✔✔any probability is a number between 0 and 1
Probability rule B - correct answer ✔✔all possible outcomes together must have probability 1
answers graded A+ passed
Frequentism - correct answer ✔✔What would happen if we did this many times?
Outcomes in the short run are ruled by chance.
But certain patterns emerge if events are repeated over and over.
Based on very many repetitions on which that outcome occurs
Truths about probability - correct answer ✔✔- chance behavior is unpredictable in the short run
- but has regular and predictable pattern in the long run
Random - correct answer ✔✔individual outcomes are uncertain, but regular distribution of
outcomes in large number of repetitions
Probability - correct answer ✔✔- a number between 0 and 1
- describes the proportion of times the outcome would occur in a very long series of repetitions
Myth of short-run regularity - correct answer ✔✔Randomness: only regular in long-run
Misleading human intuition: "I'm due for a win!"
When they don't seem to be: we look for some explanation other than chance variance
, Which of these is most probable? (HTHTTH, TTTHHH, TTTTTT) - correct answer ✔✔All equal!
(coins have to memory)
Myth of law of averages - correct answer ✔✔intuition that tells us that future outcomes must
make up for an imbalance of results
REALITY:
- there is no "must"
- nothing is forcing a coin to go one way or another on any trial (no memory)
- It is an independent event
What is the law of averages? - correct answer ✔✔a fallacy based on the assumption that events
of one kind are always balanced by events of another kind
Law of large numbers - correct answer ✔✔in a large number of "independent" repetitions of a
random phenomenon (like tossing a coin), averages are likely to become more stable as the
number of trials increases, BUT sums/counts are likely to become more variable
A probability of _______ distribution is a statistic. - correct answer ✔✔sampling
Probability that A or B happens: - correct answer ✔✔P(A) + P(B)
Probability rule A - correct answer ✔✔any probability is a number between 0 and 1
Probability rule B - correct answer ✔✔all possible outcomes together must have probability 1
