exam 2 Data

Complement - of event A, noted by the symbol A is the subset of outcomes that are not part of the event

Simple event - one that can only happen in one way, has a single outcome

mutually exclusive- a set of events that cannot occur at the same time.

Collectively exhaustive- if one of the events must occur

Certain events - is an event that is sure to occur such as “rolling a value greater than 0” for rolling one fair die

Impossible event - is an event that has no chance of occurring

Types of Probability

Priori probability - probability of an occurrence is based in having prior knowledge of the outcome that can occur

Empirical probability - based on observed data, not on prior knowledge of how the outcomes can occur

Subjective probability - differs from the other two approaches because subjective probability differs from person to person

Simple probability- occurrence of simple of a simple event A, (PA) in which each outcome is equally likely to occur

Joint probability - of an occurrence involving two or more events

Marginal Probability- an event consists of a set of joint probabilities

How many political party are there? 2 or more

Counting Rule

Rule 1: determines the number of possible outcomes for a set of mutually exclusive and collectively exhaustive events.

  • If any one of K different mutually exclusive and collectively exhaustive events can occur on each of n trails, the number of possible outcomes is equal to K^n

Rule 2: is a more general version of the first counting rule and allows the number of possible events to diff from trial to trial.

  • K1,K2,K3

Rule 3: involves computing the number of ways that a term can be arranged in order

  • n!= (n)(n-1)...(1): where n! Is called n factorial, and 0! Is defined as 1

Rule 4: the number of ways of arranging x object selected from n object in order is

  • nPx = n!

Rule 5: the number of ways of selecting x objects from n object, irrespective of order, is equal to

Permutations - number of ways in which a subset of an entire group of items can be arranged in order, possible arrangement

  • Counting rule 4

Combinations - in the order of the outcomes but only in the number of ways that x items can be selected from n items, irrespective of order, each possible selection.

  • Counting rule 5

How to read a contingency table?

A

A

total

B

TOTAL

GRAND TOTAL

Discrete Variable: is a mutually exclusive list of all the possible numerical outcomes along with the probability of occurrence of each outcome

z-score : z=

Value of x : normal distribution

  • Is not only symmetrical, but bell-shaped, a shape that (loosely) suggest the profile of a bell

Values of X: uniform distribution

  • Rectangular distribution, contains values that are equally distributed in the range between the smallest and largest values

Values of X: exponential distribution

  • Contains values from zero to positive infinity and is right skewed, making the mean greater than the median

continuous probability: vary by the shape of the area under the curve