APPLIED STATISTICS

Introduction to statistics

Measures of central tendency

Data Collection and Presentation

Deviation Measures

es the

is the science that studies data sets and
its interpretation in mathematical terms

history

Since the beginnings of civilization there have been simple forms of statistics, since graphic representations and other symbols on skins, rocks, wooden sticks and cave walls were used to count the number of people, animals or other things.

Statistics Applications

Statistics Divisions

it's a

powerful auxiliary of many sciences and
human activities

psychology

human geography

economy

Statistics is traditionally divided into

Inductive Statistics

Descriptive statistics

are

Those methods that include the collection, presentation, and characterization of a data set in order to appropriately describe the various characteristics of that set.

are

Those methods that make it possible to estimate a characteristic of a population

table

Graphical Presentation of Data A

basic concept

Graphical Presentation of Data B

following words

sample

individual

population

census

is the

I sample

set of all the elements that meet certain properties and among which it is desired to study a certain phenomenon

is the

subset of the population that is studied and from which conclusions about the characteristics of the population are drawn

Each of the elements of the sample or population

variable

Each of the traits or characteristics of the elements of a population and that vary from one individual to another

is the

study that is done directly to an entire population

A study that is done only on a sample of the population.

data

Frequency

then can by

collected in various ways: questionnaires, sampling,
censuses, observations, etc.

is the

number of times the same value is repeated

histogram

polygons

are

vertical bar diagrams in which bars are built
rectangles at the boundaries of each class.

is a

graph that joins with lines the midpoints at the top of the
histogram bars.

bar graphs

Pie chart

is the

is a

each category is described by a bar, the length of which
represents the frequency or percentage of observations that fall into a category.

, each category is described by a bar, whose length
represents the frequency or percentage of observations that fall into a category.

Steps to build a bar

• All bars must have the same width.

• The spaces between the bars should vary from half the width of a bar to the width of a bar.

• The bars must be built horizontally.

Scales and guides are useful aids in reading a graph and should be included.

• The zero point or origin must be indicated.

• The axes must have a name

Definition of Measures of Central Tendency

. Mean or Average

are

that indicate the center of a data set.

such as

• Mean or Average (the middle value).

• Median (the middle value).

• Mean or Average (the middle value).

Is calculated

adding all the data and then dividing the
total by the number of data items involved.

Median

is the

mean value of an ordered sequence of data.

Moda

is the

is the value that is repeated the most, the one that appears with the most frequency.

. The Coefficient of Variation

Variance and Standard Deviation

Definition of Deviation Measures

range

range weakness

is the

difference between the largest and smallest observation in a data set. The range measures the total spread in the data series.

is the

fails to take into account the way the data is
are actually distributed between the largest and the smallest value.

is when

take into account how the
observations.