ANSWERS SURE A+
✔✔observational study - ✔✔a study where data is collected in the present by a passive
observer
✔✔overcontrol - ✔✔having too much control over an experiment, as more overcontrol
there is more variability
✔✔population - ✔✔a set of similar items or events which is of interest for some question
or experiment
✔✔probability model - ✔✔A probability model is a mathematical representation of a
random phenomenon. It is defined by its sample space, events within the sample space,
and probabilities associated with each event. The sample space S for a probability
model is the set of all possible outcomes.
✔✔randomization - ✔✔Randomization refers to the practice of using chance methods
(random number tables, flipping a coin, etc.) to assign subjects to treatments
✔✔retrospective study - ✔✔a study using historical data, aka data collected in the past
for other purposes
✔✔sample - ✔✔a data sample is a set of data collected and the world selected from a
statistical population by a defined procedure
✔✔statistical inference - ✔✔Statistical inference is the process of using data analysis to
deduce properties of an underlying probability distribution
✔✔statistical process control - ✔✔a method of quality control which employs statistical
methods to monitor and control a process
✔✔tampering - ✔✔responding to variance to lower the variance will actually make
variability increase
✔✔time series - ✔✔A time series is a series of data points indexed (or listed or
graphed) in time order
✔✔variability - ✔✔successive observations of a system or phenomenon do not produce
exactly the same result
✔✔addition rule - ✔✔P(A u B) = P(A) + P(B) - P(A n B)
, probability of A + probability of B - the intersection of A & B because (A n B) is counted
twice in P(A) + P(B)
✔✔combination - ✔✔a selection of r items from a set of n where order does not matter
nCr
✔✔equally likely outcomes - ✔✔whenever a sample space consists of N popssible
outcomes that are equally likely, the probability of each outcome is 1/N
ex: throw of a fair dye
✔✔event - ✔✔an event is a set of outcomes of an experiment (a subset of the sample
space) to which a probability is assigned
✔✔independence - ✔✔if the events E1 and E2 are independent, then P(E1 n E2) =
P(E1)*P(E2)
the outcome of one event does not effect the outcome of another event
✔✔outcome - ✔✔an outcome is a possible result of an experiment
✔✔probability - ✔✔the sum of the probabilities of the outcomes in the event
✔✔random experiment - ✔✔a procedure that is carried out under controlled conditions,
is executed to discover an unknown result, and results in DIFFERENT outcomes even
when repeated in the same manner every time
✔✔discrete sample space - ✔✔a sample space that consists of a finite or countable
infinite set of outcomes
✔✔discrete random variable - ✔✔a variable with a finite or countably infinite range. its
values are obtained by counting
number of scratches on a surface
number of defective parts among 100 tested
✔✔continuous sample space - ✔✔a sample space that contains an interval of real
numbers
✔✔continuous random variable - ✔✔a variable with an interval(either finite or infinite) of
real numbers for its range. its values are obtained by measuring
electrical current and voltage
time