Data Collection and Presentation (Basic concepts (Population ( It is the…
Data Collection and Presentation
It is the set of all the elements that fulfill certain properties and between which it is desired to study a certain phenomenon (they can be homes, number of
Screws produced by a factory in a year, throwing of a coin, etc.).
It is the subset of the population that is studied and from which conclusions are drawn on the characteristics of the population.
Each of the elements of the sample or population (people, screws, hospitals, shops) and on which the observation will fall.
Each of the characteristics or characteristics of the elements of a population and that vary from one individual to another (salary, eye color, sex, number of children).
It is a study that is done directly to an entire population.
It is a study that is done only to a sample of the population. If the sample is representative, the results obtained will be the same or very close to those that would be obtained from a census.
The data can be collected in several ways: questionnaires, sampling,
Censuses, observations, etcetera. Be that as it may, after being collected, they must be
Summaries to facilitate their analysis.
La frecuencia es la cantidad de veces que se repite un mismo valor.
Graphical Presentation of Data - Part A
Histograms are vertical bar diagrams in which rectangular bars are constructed at the boundaries of each class.
A polygon is a graph that joins the midpoints at the top of the histogram bars with lines.
Graphical Presentation of Data - Part B
In the bar chart, each category is described by a bar, whose length
Represents the frequency or percentage of observations falling into a category.
To construct a bar graph the following suggestions are made:
The bars must be constructed horizontally.
• All bars must be the same width.
• The spaces between the bars must vary between half the width of a bar
To the width of a bar.
• Scales and guides are useful aids in reading a graph and should be
• The zero point or origin must be indicated.
• Axes must be named
A circular or pie chart is a circle divided into parts representing the
Relative frequency or percentage of different categories.