# Stats. Test 1

## 28 terms

### Statistics

Any descriptive measurement taken from a subset of elements of a population.

### Sample

Subset of a population, where a population is the set of all objects or subjects under study.

### Census

Involves gathering data from the entire population, a complete coverage.

### Descriptive Statistics

Methods of organizing, summarizing, and presenting data in an informative way.

### Inferential Statistics

Methods used to determine something about a population on the basis of a sample.

### Parameter

A descriptive measurement from a population.

### Statistic

An estimate of the actual value of the parameter.

### Error

The difference between the value of the parameter and the statistic.

### Mutual Exclusivity

A property of a set of categories such that an individual or object can be classified into only on of the existing categories.

### Collectively Exhaustive

Situation where every member of the population or sample must appear in one of the categories.

### Levels of Measurement: Nominal

a) Categories that are mutually exclusive and exhaustive.

### Levels of Measurement: Ordinal

a) Categories that are mutually exclusive and exhaustive.
b) Data has logical order.

### Levels of Measurement: Interval

a) Categories that are mutually exclusive and exhaustive.
b) Data has logical order.
c) Equal differences in the characteristic are represented by differences in measurement.

### Levels of Measurement: Ratio

a) Categories that are mutually exclusive and exhaustive.
b) Data has logical order.
c) Equal differences in the characteristic are represented by differences in measurement.
d) The zero point corresponds to the absence of the characteristic.
e) A ratio of measurements has a meaning.

### Data

Grouped: Have been organized into a frequency distribution

### Element

The basic unit that compromises and defines a population.

### Frequency Distribution

Grouping of data into mutually exclusive classes showing the number of observations in each.

k=1+3.3log(n)

### Interval Width (i)

(i)greater than,equal to ((Max(X)-Min(X))/K

### Histograms

Graphical representation of a frequency distribution for continuous data.

### Relative Frequency Distribution

Shows the fraction of the total number of observations in each class.

### Class Midpoint

Halfway between the lower limit of two consecutive classes.

### Class Interval

Subtract the lower limit of a class from the lower limit of the next class.

### Frequency Polygon

Consists of line segments connecting the points formed by the intersection of the class midpoints and the class frequencies.

### Cumulative Frequency Distribution

Tells how many elements are classified to be equal or lower to the upper limit of a given class.

### Laws of Large Numbers

For a large enough (n) there is a large probability that the estimator is close to the value of the parameter.

### Time Series

A series of values of a variable at successive times. Line graphs are used to map these.

### Bar Chart

Graphical representation of a frequency distribution for discrete data.