chapter 01 - introduction
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DESCRIPTIONIntroductory chapter: what is statistics?
The term we know today, statistics, is of Latin descent. It comes from the word status, which means
state or condition (hence the term status quo, which means the state in which). While the term only
became widely used during the 18th century, the practice had been around many centuries prior to
that. In fact, as early as the biblical times, people had been using statistics in order to help with the
administration of the state. For example civilized states would collect data on taxes, population
count, poultry and livestock, labor, resources, and agricultural products, as they realized that these
figures helped greatly in governance.
In no way did the discipline become obsolete. As a matter of fact, the use of statistics has become
more widespread in the government these days. Due to advancements in data collection techniques
and statistical programming tools, the amount and scope of data have greatly increased, thereby
allowing more and more avenues for its application. Now, countries regularly release data on gross
domestic product, consumer price index, inflation, unemployment rates, foreign exchange rates,
interest rates, and population counts. These data do not only monitor the performance of a certain
country, but they also help lawmakers and public officials make crucial policy changes or proposals.
The use of statistics is not limited to the government, though. Where data is needed and analyzed,
statistics would most likely be used. The following are some examples of applications of statistics:
Medicine. In order to develop new drugs, researchers use statistics to determine
effectiveness. Studies on the spread of certain diseases, together with studies for prevention,
diagnosis, and treatment, also use statistical analyses.
Economics. The field heavily relies on statistical methods, as economists analyze data in
order to understand the workings of both foreign and local economic climate. As such,
estimation of indicators such as inflation rate, interest rates, foreign exchange rates, and
gross domestic product.
Business. Other than market studies for launching new products and campaigns, businesses
also use statistics in order to ensure that their products are at par with certain standards.
Businesses also forecasts certain indicators, usually those related to production, that would
help them make decisions with regard to policies and actions for the firm.
Politics. As the election period draws near, politicians seek the help of survey and polls in
order to determine how they are faring compared to their competitors. This type of
information helps them formulate the tactics they would use in order to win the voters over.
The list of the uses of statistics would go on, and it would most probably keep on going. As long as
data is available, statistics would never run out of uses. As such, it is very important to possess some
knowledge in statistics.
Chapter I: Introductory Concepts
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Whenever we hear the word statistics, several things immediately come to mind. It could be the vital
statistics of a beauty pageant contestant. It could be the season statistics of your favorite football
team. It could be the interviewer that comes knocking on your door to ask you questions. While
these are still connected to the discipline, statistics is not limited to any of these. What, then, is
Definition. Statistics is the branch of science that deals with the collection,
organization, analysis, interpretation, and presentation of data.
From the definition above, statistics may sound like a highly technical courseas though it is
something that is not really applicable to our daily lives. This notion cannot be more incorrect, as we
apply and encounter statistics, even in the most dismal aspects of our lives.
Why is it important to study statistics? It is important because statistics give us the information that
we need. The information gathered would then enable people to make intelligent decisions. How is
this information obtained? The information is obtained through a process called statistical inquiry.
The process would help us answer problems and understand things a lot better. More specifically, it
would help us gain better understanding about a particular group of elements that is of interest to us.
That particular group of elements is called the population.
Definition. The population is the collection of all elements in a statistical inquiry.
Definition. The sample is a subset of the population.
The population is a big group which may contain individuals, objects, animals, or geographic areas, to
name a few. The following are some examples of populations:
Collection of all school-aged children in Metro Manila
Collection of Statistics 101 students currently enrolled
Set of fluorescent bulbs manufactured in a month
While we would like to use information culled directly from the population, this is not always
possible, since it costs a lot of money and time. Thus, we resort to using a subset of the population
which is the sample. Some examples of samples for each of the population specified above are as
1325 school-aged children in Metro Manila
80 Statistics 101 students currently enrolled
100 light bulbs manufactured in a month
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Definition. The variable is a characteristic or attribute of an element that can assume
different values for different elements.
Definition. The observation is a realized value of a variable.
Definition. The data is the collection of observations.
Using the data on hand, we can then compute for a summary measure that would describe either the
population or the sample. These summary measures describe a certain characteristic of the
population or the sample. These are the parameter and the statistic. The parameter is for the
population while the statistic is for the sample.
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FIELDS OF STATISTICS
Statistics has two major fieldsapplied statistics and mathematical or theoretical statistics. Applied
statistics is concerned with the procedures and techniques used to collect, organize, analyze,
interpret, and present data. This allows us to properly select and implement the tools needed in
order to obtain solutions to the research problem. Mathematical or theoretical statistics, on the
other hand, deals with the development of the theoretical foundations of the methods used in
statistics. It is very important to also study theory because it is essential to understand the rationale
behind the methods. Studying these theories would allow us to develop new methods or modify
existing methods in order to keep up the new and more complex problems.
Applied statistics, likewise, has two major areas. These are descriptive statistics and inferential
Descriptive statistics are techniques used in the collection, organization, presentation, analysis, and
interpretation of data. Conclusions drawn using descriptive statistics are only applicable to the data
on hand. No generalizations can be made to larger group.
On the flip side, inferential statistics are techniques used in analyzing data that would allow us to
generalize to a larger group. Here, conclusions are made with a degree of uncertainty because the
information we have is partial. As such, these conclusions are subject to some error.
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THE STATISTICAL INQUIRY
As mentioned earlier, it is through the statistical inquiry that we obtain information. Once the
process is done, we expect to have gained a better understanding of some things or characteristics
we are interested in.
A statistical inquiry is a planned research that provides information in order to answer a research
problem. Whenever we perform an inquiry, our goals fall under one or more of the following general
Describe characteristics using a certain measure
Compare characteristics between two groups
Justify an assertion
Determine relationships between two variables
Identify groups of related variables
Reveal natural groupings with respect t values of a certain variable
Determine effects of one variable on another
Clarify patterns with the help of graphs
Predict values of a variable of interest using other variables
Forecast values of a variable through time
Because statistics is a branch of science, it is expected that a statistical inquiry would follow steps
very much like the scientific method or other problem-solving tools.
1. Identify the problem.
2. Plan the study.
3. Collect the data.
4. Explore the data.
5. Analyze the data and interpret results.
6. Present the results.
Indentifying the problem is the heart of a statistical inquiry. This problem can be in the form of either
a question or a statement. While many think that cooking up a problem would be very easy, that is
not the actual case, since more than anything, it needs much thought. It is the most important to
think of the problem thoroughly because the research problem would be the basis for all the actions
in a statistical inquiry. If