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25 Cards in this Set
 Front
 Back
Population (*)

Any set of objects (mainly sets of numbers, measurements, or observations)


Sample (*)

A part of a population which is a good representation of the population (should be RANDOM)


Inference

Based on information gained in the sample, we make an inference about the population


Variable

A characteristic of each individual element of a population or sample


Parameter (*)

A numerical characteristic of the entire population (generally unknown)


Statistic

A numerical characteristic of a sample (always calculable from the sample data)


Random sample (*)

A sample chosen in such a way that every element in the population has the same chance of being selected


Systematic sample

A sample in which every kth item in the sampling frame is selected


Stratified sample

A sample obtained by stratifying the sampling frame and selecting a fixed number of elements from each of the strata using random samples


Chebyshev's Theorem

The proportion of any distribution that lies within 'k' standard deviation of the mean is at least 1(1/k), where k is less than or equal to one


Empirical Rule (*)

If a set of measurements possesses a moundshaped histogram, ~68% of the measurements lie within one S.D. of the mean; ~95% of the data lies within two S.D. of the mean; almost all of the data lies within three S.D. of the mean.


How do you estimate the standard deviation?

Divide the range of the data by four


What does it mean if r = 0 for a set of bivariate data?

There is no linear relationship/correlation.


What is 'r'?

The Correlation Coefficient


Random Experiment (**)

An operation whose outcome cannot be predicted with certainty


Sample Space

The set of all possible outcomes of an experiment


Event

Any subset of the sample space (or any collection of outcomes)


Mutually Exclusive

Two events are mutually exclusive if they cannot occur at the same time (have no common elements)


How do you prove two events to be independent?

1.Calculate P(A)
2.Calculate P(B) 3.Calculate P(A and B) Check if P(A and B)=P(A)P(B); if equal, independent; if not equal, dependent 

Complement of an Element

A is a subset of the sample space; the complement of A is the set of all elements not included in A


Independent Events

Two events are independent if the occurrence (or nonoccurence) of one does not change the probability of occurrence of the other.


If two events are mutually exclusive, what is the value of P(A and B)?

Zero


Random Variable (*)

A variable whose value is determined by a random experiment


Range of Random Variables

The set of all possible outcomes of random variables (NOT highestlowest value!)


Discrete Random Variable (*)

A random variable is discrete when number of elements in its range can be counted.
