This document discusses observational and experimental studies. Observational studies involve observing subjects without manipulation, while experimental studies involve manipulating variables to test causation. Some key points about observational studies are that they are less expensive but can take years, provide rich detailed data, and establish correlations but not causation. Experimental studies allow determining causation but are more expensive, time-consuming, and raise ethical concerns due to manipulation. Examples provided include observing children at a playground for an observational study and testing a new teaching method versus a control group in a statistics course for an experimental study.

1. Observational and Experimental Studies
The University of Burdwan
Dept. of Comp. Sc. & App.,
1st Sem,
Presented by:
Soumi Samanta & Sourav Monda

2. Introduction
A statistical study in statistics with a population refers to the process of
collecting, analyzing, and interpreting data from a specific group of
individuals or objects in order to draw conclusions or make inferences
about that population. This type of study typically involves sampling a
subset of the population and collecting data from that sample in order
to make estimates or predictions about the population as a whole.
Statistical techniques, such as hypothesis testing and regression analysis,
are often used in this type of study to help researchers understand the
characteristics and patterns within the population.

3. The study we conduct to perform statistical analysis of our data can majorly
be of two types — Observational and Experimental.

4. In this type of study, we measure or survey members of a
sample without trying to affect the members or
manipulating the variables. Here, we simply observe what
is happening and record the observations. So, it would
be correct to say that researchers do not impose any
kind of treatment or restriction to the group nor do
they randomly assign the subjects to a group. There is
basically no manipulation of the environment in which
the subject occurs.
Observational Study

5. Some of the key points about
observational studies are as follows:
Observational studies are less expensive
than experimental studies.The time
required for the completion of
observational studies can be several
years to decades.

6. Pros of Observational Study
1. Observation studies can provide rich and detailed data about a particular phenomenon. Because they
involve directly observing and recording the behaviors or characteristics of interest, they can provide
a more complete picture than other methods like surveys or experiments.
2. Observation studies can be used to study a wide range of topics, including human behavior, animal behavior,
and natural phenomena.
3. Observation studies can be conducted in a variety of settings, including natural environments, laboratory
settings, or online. This flexibility allows researchers to study a wide range of phenomena and to choose the
most appropriate setting for their study.
4. Observation studies can be less expensive and time-consuming to conduct than other types of research, such
as experiments, which may require the creation of complex designs and the manipulation of variables.
5. Observation studies can be useful for generating hypotheses or ideas for further research, as they can
provide a starting point for more in-depth investigations.

7. Cons of Observational Study
1. Observation studies can be subject to observer bias, which refers to the influence that the observer's own
beliefs, expectations, or preferences may have on their observations. To minimize observer bias,
researchers may use techniques like training observers to be consistent in their observations, using
multiple observers to cross-check each other's observations, or using objective measures whenever
possible.
2. manipulating variables and testing specific hypotheses. Observation studies may be limited in their ability
to establish cause-and-effect relationships, because they involve simply observing and recording what is
happening rather than
3. Observation studies can be time-consuming, especially if they involve observing behaviors or phenomena
over an extended period of time.
4. Observation studies may be subject to ethical considerations, particularly when they involve human
subjects. Researchers must ensure that they have obtained informed consent from participants and that
they are protecting their privacy and confidentiality.
5. Observation studies may be limited in their ability to measure certain variables or characteristics that are
difficult to observe directly, such as attitudes or beliefs. In these cases, researchers may need to use other
methods, like surveys or experiments, to measure these variables.
6. Observation studies may be limited in their ability to measure certain variables or characteristics that are
difficult to observe directly, such as attitudes or beliefs. In these cases, researchers may need to use other
methods, like surveys or experiments, to measure these variables.

8. Example of Observational study
An example of an observational study in real life could be a researcher studying the
behavior of a group of children in a playground. The researcher would observe the children
as they play, taking note of their actions and interactions with one another. They might also
gather additional data through interviews with the children or their caregivers, or by
collecting information about the children's backgrounds and experiences. This type of study
allows the researcher to gather data about the children's behavior in a natural setting,
without manipulating any variables or attempting to control the environment. The results of
the study could be used to better understand how children interact with one another and
how their behavior is influenced by various factors.

9. In this type of study, we randomly assign a treatment to a group so
that the researchers can draw the cause and effect (causal)
conclusion. This random assignment of treatments is what
distinguishes both the studies (observational and experimental).
Here, we experiment and manipulate the environment of the subject to
measure the response (dependent) variable. Evidence provided by the
experimental study is considered to be stronger than the
observational study..
Experimental Study

10. Some of the key points about experimental
studies are as follows:
Experimental studies are closely
monitored.Experimental studies are
expensive.Experimental studies are
typically smaller and shorter than
observational studies

11. Pros of Experimental Study
1. Can establish cause and effect relationships: Experimental studies allow researchers to
manipulate variables and observe the effect on the outcome, allowing them to establish a
causal relationship between the two.
2. Higher control over variables: Researchers have more control over variables in experimental
studies, as they can manipulate and control the conditions under which the experiment is
conducted. This allows for more accurate and reliable results.
3. Greater generalizability: Experimental studies can be replicated and conducted in different
settings, allowing for the results to be generalized to a larger population.
4. Ability to control for extraneous variables: Experimental studies can control for extraneous
variables by using random assignment, ensuring that any differences between groups are due
to the experimental manipulation and not other factors.
5. Greater precision: Experimental studies often have larger sample sizes and more rigorous
methods, leading to more precise results.

12. Cons of Experimental Study
1. Limited generalizability: Experimental studies are designed to test specific hypotheses or treatments
in a controlled setting, which means the results may not be applicable to a larger population.
2. Ethical concerns: Some experimental studies may involve manipulating variables or exposing subjects
to potentially harmful conditions, which raises ethical concerns.
3. Limited flexibility: Experimental studies are often highly structured and controlled, which means there
is limited flexibility to change the design or variables being tested.
4. High cost: Experimental studies can be expensive to conduct, as they often require specialized
equipment, materials, and trained personnel.
5. Time-consuming: Experimental studies can take a long time to complete, as they involve careful
planning, data collection, and analysis.
6. Limited accuracy: Experimental studies may not always be completely accurate, as they are subject to
various sources of error such as measurement error, sampling error, and confounding variables.

13. Example of Experimental Study
An experimental study is a type of research method in which the researcher manipulates one or more variables
and measures the effect on one or more other variables. Experimental studies are used to establish cause and
effect relationships between variables.
Here is an example of an experimental study in the field of statistics:
A researcher is interested in the effect of a new teaching method on student performance in a statistics course.
The researcher recruits a sample of students and randomly assigns half of them to the experimental group,
which will receive instruction using the new teaching method. The other half of the students are assigned to
the control group, which will receive instruction using the traditional teaching method. Both groups are tested
on their knowledge of statistics at the beginning and end of the course. The researcher compares the scores of
the two groups to determine if the new teaching method has a statistically significant effect on student
performance.
This is a simple example, but experimental studies can be much more complex and can involve multiple
independent and dependent variables.