Business Statistics - Cheat Sheet
Exam 8th October 2021 - Online
Exam stuff
● IQ question
● Probability → P( … ≤ X ≤ …) or P(X≤5)
● PMF, compute the expectation
● Confidence Interval, what does it mean
● Sample mean, sigma, what happens when increase/decrease sigma
● Hypothesis questions
● Python code, answer what the solution could be
, Probability & Random Values
Sample space (Ω) = the set of all possible outcomes
Example Tossing a coin → Ω = {H, T}
Events (A) = subset of Ω.
Example Only heads → A = {H}
𝑛𝑢𝑚𝑏𝑒𝑟𝑠 𝑜𝑓 𝐴
Formula Probability of an A = P = 𝑡𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 Ω
● P(Ω)= 1, because Ω is a set of all possible outcomes
● P is always between 0 and 1
● If A ⊂ Ω → A is a subset of Ω
Random Value = a random number from one of the outcomes of a
random experiment.
Discrete RV = that takes only discrete, finite or at most
countably infinite number of values
● These values are counted
● Number of students attending in a class in a given day
● Number of customers in a store in a given day
● Number of clicks per hour
Continuous RV = can take on a continuum of values rather than
finite or countably finite numbers. They can take values in the whole
real number line or within a particular interval.
● These values are measured
● Height and weight
● Liters of milk produced by a cow
● Daily temperature
● Always estimate the P that it lies between two values
Exam 8th October 2021 - Online
Exam stuff
● IQ question
● Probability → P( … ≤ X ≤ …) or P(X≤5)
● PMF, compute the expectation
● Confidence Interval, what does it mean
● Sample mean, sigma, what happens when increase/decrease sigma
● Hypothesis questions
● Python code, answer what the solution could be
, Probability & Random Values
Sample space (Ω) = the set of all possible outcomes
Example Tossing a coin → Ω = {H, T}
Events (A) = subset of Ω.
Example Only heads → A = {H}
𝑛𝑢𝑚𝑏𝑒𝑟𝑠 𝑜𝑓 𝐴
Formula Probability of an A = P = 𝑡𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 Ω
● P(Ω)= 1, because Ω is a set of all possible outcomes
● P is always between 0 and 1
● If A ⊂ Ω → A is a subset of Ω
Random Value = a random number from one of the outcomes of a
random experiment.
Discrete RV = that takes only discrete, finite or at most
countably infinite number of values
● These values are counted
● Number of students attending in a class in a given day
● Number of customers in a store in a given day
● Number of clicks per hour
Continuous RV = can take on a continuum of values rather than
finite or countably finite numbers. They can take values in the whole
real number line or within a particular interval.
● These values are measured
● Height and weight
● Liters of milk produced by a cow
● Daily temperature
● Always estimate the P that it lies between two values
