STA304 H1 S/1003 H S

Summer 2017

Dragan Banjevic

Introduction into basic ideas (I)

Note: A lot of material is used from the Internet, some with reference, some without.

    Sample Survey Design Introduction Into Basic Ideas (I)

1) Sample Survey is a partial investigation of the finite population using a sample. The purpose of the sample survey is to obtain information about the population.

Surveys about:

Introduction Into Basic Ideas (II)

2) Population is a group of units defined according to the aims and objectives of the survey.

Examples of populations:

3) Sampling is the selection of part of the population (selection of units from the population).If you want to learn more check out Determine which cps are mins or maxes?

4) Sampling Method is a scientific and objective procedure of selecting units from a population. It provides a sample that is expected to be representative of the population as a whole. It also provides procedures for estimation of the population parameters.

Example (Nutr J. 2007; 6: 35): A survey of energy drink consumption patterns among college students ( 1 )

The purpose: To determine energy drink consumption patterns among college students (prevalence and frequency) for six Don't forget about the age old question of canvas uthscsa login

Situations:

and prevalence of adverse side effects and energy drink use dose effects among college energy drink users

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Example: Energy drink consumption (II)

Methods: Responses to 19 item survey from 496 randomly surveyed college students attending a state university in the Central Central Atlantic Atlantic region of the United States.

Some Results

Energy drink user (more than one energy drink each month for the current semester ): 51% Users consumed energy drinks for:

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Reported ever having headaches (22%)

Conclusions: … side effects from consuming energy drinks are fairly common, … Future research should identify …

Review Of Basic Notions From Statistics (I)

Population: Set (group) of elements (units) of our interest

Units: Elements of the population

Variable, Measurement, Characteristic, Property: Function defined on population elements, characteristic of population elements.

Variable can be – quantitative (numerical) or qualitative (categorical).

Variable Range: Set of variable values, i.e. all values the variable can take.

Example

Population:

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Variables of interest:

Area of study, grade, age,

height, weight, sex, …

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Review Of Basic Notions From Statistics (II)

Notation

Population: E = {e1, e2, e3, ... , eN}         Population size: N

Elements e, e                                 Variables: y x z t i Variables: y, x, z, t, …

Range: {y(e) : e E}                                 e → y(e), x(e), …

Distribution, frequency distribution: Proportion/percentage of elements with value in an interval [a,b], for any a and b

Discrete variable:        Prop()

Continuous variable: Prop (a,b) = Prop(a<y≤b) =

density function