STAT 503 Final EXAM QUESTIONS
WITH DETAILED VERIFIED
ANSWERS (100% CORRECT
ANSWERS) / ALREADY GRADED A+
Is a quantitative variable always measured in numbers? ✔✔Yes
Is any measurement that you record from a sample a variable? ✔✔False
What is a statistic? ✔✔The measure that is taken from the whole sample as a summary of
the sample
Sample data skewed to the left, then longer tail is at the... ✔✔Left
What is sensitive to outliers? ✔✔Median
Formula to calculate standard deviation ✔✔s = sqrt(sum(x1-xbar)^2 / n-1)
How to calculate degrees of freedom? ✔✔n-1
What is the first quartile? ✔✔Median of lower half
What is the third quartile ✔✔Median of upper half
What is included in a box plot summary? ✔✔Q0 = minimum
Q1 = median of lower half
Q2 = median
Q3 = median of upper half
Q5 = maximum
, What is the the interquartile range (IQR)? ✔✔Q3 - Q1 (shown inside box plot)
What is an outlier? ✔✔Any data that is Q3 + 1.5IQR or Q1 - 1.5 IQR
When is a phenomenon random? ✔✔When it has uncertain outcomes in a short run
(sample) but show regular distribution in a long run (population)
What is an outcome? ✔✔Observation of a variable
What is a probability model? ✔✔A mathematical description of a random phenomenon
consisting of 2 parts (sample space and way of assigning probability to event)
What is the multiplication rule? (independent) ✔✔P(AB) = P(A) P(B|A) = P(B) P(A|B)
What is the addition rule? (disjoint) ✔✔P(A or B) = P(A) + P(B) - P(AB)
If A and B are disjoint, the must be dependent. ✔✔TRUE
Why is a probability tree diagram used? ✔✔To show multiple variables according to stages
(the order that they happen)
What is written on each segment in a probability tree? ✔✔A conditional probability
What probability is at the end of the branch on a probability tree? ✔✔The product of the
probabilities of the segments of that branch
What are all ultimate outcomes of probability tree? ✔✔Disjoint outcomes, non-overlapping
"Sensitivity" (HIV example) ✔✔P(T+| HIV+)
WITH DETAILED VERIFIED
ANSWERS (100% CORRECT
ANSWERS) / ALREADY GRADED A+
Is a quantitative variable always measured in numbers? ✔✔Yes
Is any measurement that you record from a sample a variable? ✔✔False
What is a statistic? ✔✔The measure that is taken from the whole sample as a summary of
the sample
Sample data skewed to the left, then longer tail is at the... ✔✔Left
What is sensitive to outliers? ✔✔Median
Formula to calculate standard deviation ✔✔s = sqrt(sum(x1-xbar)^2 / n-1)
How to calculate degrees of freedom? ✔✔n-1
What is the first quartile? ✔✔Median of lower half
What is the third quartile ✔✔Median of upper half
What is included in a box plot summary? ✔✔Q0 = minimum
Q1 = median of lower half
Q2 = median
Q3 = median of upper half
Q5 = maximum
, What is the the interquartile range (IQR)? ✔✔Q3 - Q1 (shown inside box plot)
What is an outlier? ✔✔Any data that is Q3 + 1.5IQR or Q1 - 1.5 IQR
When is a phenomenon random? ✔✔When it has uncertain outcomes in a short run
(sample) but show regular distribution in a long run (population)
What is an outcome? ✔✔Observation of a variable
What is a probability model? ✔✔A mathematical description of a random phenomenon
consisting of 2 parts (sample space and way of assigning probability to event)
What is the multiplication rule? (independent) ✔✔P(AB) = P(A) P(B|A) = P(B) P(A|B)
What is the addition rule? (disjoint) ✔✔P(A or B) = P(A) + P(B) - P(AB)
If A and B are disjoint, the must be dependent. ✔✔TRUE
Why is a probability tree diagram used? ✔✔To show multiple variables according to stages
(the order that they happen)
What is written on each segment in a probability tree? ✔✔A conditional probability
What probability is at the end of the branch on a probability tree? ✔✔The product of the
probabilities of the segments of that branch
What are all ultimate outcomes of probability tree? ✔✔Disjoint outcomes, non-overlapping
"Sensitivity" (HIV example) ✔✔P(T+| HIV+)
