mmw 1st sem midterms

STATISTICS

Is the branch of science that deals with the collection, presentation, organization, analysis and interpretation of data

DATA

Are the facts and figures collected, analyzed and summarized for presentation and interpretation

POPULATION

-Is the collection of all elements under consideration in a statistical inquiry

Sample-

is a subset of the population

POPULATION

-Consists of all subjects under study

Descriptive Statistics-

§are used to describe the basic features of the data in a study. They provide simple summary about the sample and the measures.

Inferential Statistics-

includes all the techniques used in analyzing the sample data that will lead to generalization about a population from which the sample came from

VARIABLE

Is a characteristics or attributes of the elements in a collection that can assume different values for the different elements

MEASUREMENT

§Is the process of determining the value or label of the variable based on what has been observed

Primary Data

§it includes government agencies, business establishments, organizations and individuals who carry original data or who have the firsthand information relevant to a given problem

Secondary Data-

data obtained from secondary source like newspapers, magazines, journals and republished materials.

The Interview Method

is a person-to-person encounter between the one soliciting information and the one supplying the data. It could either be personal interview or a telephone interview.

The Questionnaire Method

it utilize questions to obtain information. They are either mailed or hand-carried to the intended participants.

The Observation Method-

data pertaining to behaviors of an individual or a group of individuals at the time of occurrence of a given situation are best obtain by direct observation.

The use of Documents-

researchers who make use of vital statistics, such as the number of households, birth rates, death rates and marriages.

The Method of Experimentation-

data needed to answer questions through series of experimentations.

The textual form-

this is utilized when the data to be presented are purely qualitative or when very few number are involved.

The tabular form-

it is used when people want to make comparisons and draw relationships.

The graphical form

the graph or chart is perhaps the most effective device for attracting people attention.

Target Population-

is the population we want to study

Sampled Population-

is the population from where one actually select the sample

Probability Sampling-

is a method of selecting a sample wherein each element of the population has a known, nonzero chance of being included in the sample

arithmetic mean

is the most common type of average. It is the sum of all the observed values divided by the numbers of observations.

median

is the value that divides the array into equal parts.

mode

is the observed value that occurs with the greatest frequency in a data set

Measures of central tendency

are descriptive measures that are used to describe the center of a set of data.

Measures of Location

on positive fractiles are used to specify the location of specific data in relation to the rest of the sample. It divides the distribution into equal number of parts.

percentiles

divide the ordered observation into 100 equal parts.

quartiles

divide the ordered observations into 4 equal parts.

decile

divides the ordered observation into 10 equal parts.

Measures of Dispersion or Variability

describes the spread or the scatterings of the values around the mean.

range

is the distance between the maximum value and the minimum value.

variance

is the average squared difference of each observation from the mean

standard deviation

is the positive square root of the variance

coefficient of variation

is the ratio of the standard deviation to the mean, expressed as a percentage

Measures of Skewness

measures the degree of symmetry of a distribution.

sk = 0

symmetric distribution

sk > 0

positively skewed distribution

sk < 0

negatively skewed distribution

Symmetrical or Normal Distribution

In a symmetrical distribution the mean, median and mode all fall at the same point or equal.

Positively Skewed Distribution

In a positively skewed distribution the extreme scores are larger, thus the mean is larger than the median

Negatively Skewed Distribution

The order of the measures of central tendency would be the opposite of the positively skewed distribution with the mean being smaller than the median, which is smaller than the mode

zero skewness

mode = median = mean

positively skewed

§Mean and Median are to

the right of the Mode.

Mode

Negatively Skewed

Mean and Median are to the left of the Mode.

Mode

positively skewed

Measures of Kurtosis

refers to the peakedness or flatness of the curve of the distribution

when K > 3,

Leptokurtic

when K = 3

Mesokurtic

when K < 3

Platykurtic

Leptokurtic-

the curve is more peaked and the hump is narrower or sharper than the normal curve.

Platykurtic-

the curve is less peaked and the hump is flatter than the normal curve

Mesokurtic-

the hump is the same as the normal curve. It is neither too flat nor too peaked

problem

is a situation that confronts the learner that requires resolution, and for which the path to the answer is not immediately known.