STAT 1430.01 MIDTERM (EXPERIMENTS) EXAM QUESTIONS AND ANSWERS. VERIFIED 2025/2026.

STAT 1430.01 MIDTERM
(EXPERIMENTS) EXAM QUESTIONS
AND ANSWERS. VERIFIED 2025/2026.




Variables are either... - ANS Quantitative or Categorical


Quantitative Variables - ANS numerical things


Categorical Variables - ANS names or labels, not numbers,m puts individuals into groups


GRAPH: Histogram - ANS Horizontal Axis = value of variable
Vertical Axis = # or % in each group (5-10 bins is enough)


GRAPH: Boxplot - ANS Divides data into quarters, 5 number summary
- bigger boxes don't mean more data....
- you cannot SEE THE MEAN
- does not show symmetry
- good for skewed data sets


What is the 5 number summary for a boxplot? - ANS 1) Minimum
2) Q1
3) Median


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, 4) Q3
5) Max


What can you not see on a boxplot? - ANS THE MEan


How do we describe quantitative data? - ANS 1) Shape = symmetric, skewed left, skewed
right
2) Center = mean and median
3) Variability = standard deviation and IQR


Time-Series Plot - ANS Horizontal Axis: Time
Vertical Axis: Value of the Variable


Mean (x-bar) - ANS total / # of observations
- SAME UNITS!


Median (M) - ANS 50th percentile, Q2 in the middle


Mean = Median (Shape) - ANS SYMMETRIC


Mean > Median (shape) - ANS SKEWED RIGHT


Mean < Median (shape) - ANS SKEWED LEFT


DEF: Standard Deviation (s) - ANS concentration around the mean....how spread out numbers
are


Standard Deviation things to remember - ANS - CAN NEVER BE NEGATIVE


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