Question

When it come to the process of sampling and testing hypotheses using a sample.

• What causes the findings of a sample-based research to be suspect?

• What are the consequences of having a non-representative sample and testing hypotheses for decision making?

• How dangerous could this prove to be? (Provide examples.)

Answer 1

What causes the findings of a sample-based research to be suspect?

Hypothesis is about challenging the status quo, or a claim against what is currently happening. A hypothesis is an educated guess about something in the world around you. It should be testable, either by experiment or observation. For example:

• A new medicine you think might work.
• A way of teaching you think might be better.
• A possible location of new species.
• A fairer way to administer standardized tests.

If you are going to propose a hypothesis, it’s customary to write a statement.
For example:

• If I (decrease the amount of water given to herbs) then (the herbs will increase in size).
• If I (give patients counseling in addition to medication) then (their overall depression scale will decrease).

good hypothesis statement should:

• Include an “if” and “then” statement.
• Include both the independent and dependent variables.
• Be testable by experiment, survey or other scientifically sound technique.
• Be based on information in prior research (either yours or someone else’s).
• Have design criteria (for engineering or programming projects).

What are the consequences of having a non-representative sample and testing hypotheses for decision making?

For instance, let us select people randomly from all regions(Asia, America, Europe, Africa etc.) on earth to study height , our estimate will be close to the actual estimate and can be assumed as a sample mean, whereas if we make selection let’s say only from the United States, then our average height estimate will not be accurate but would only represent the data of a particular region (United States). Such a sample is then called a biased sample and is not a representative of “population”. When researchers fail to select their participants at random, they run the risk of severely impacting the validity of their results and findings because their sample does not accurately reflect the population of interest.

How dangerous could this prove to be? (Provide examples.)

As mentioned above when researchers fail to select their participants at random, they run the risk of severely impacting the validity of their results and findings because their sample does not accurately reflect the population of interest.

One of the most powerful and famous examples of  non-representative sample being committed on a grand and impactful scale occurred during the Truman-Dewey United States presidential race of 1948.

During the race, a political telephone survey was conducted nationwide. The results of the survey implied that Dewey would win over Truman in a heavy-handed landslide; however, the study failed to account for the fact that telephones were still a fairly revolutionary and expensive form of technology.

Due to the cost of telephones in 1948, only a small number of wealthy families owned them and kept them in their homes. Therefore, the political telephone survey was only presented to participants that were part of relatively wealthy families, and at the time, wealthy families tended to support Dewey while lower-middle class to lower class families were more likely to support Truman.

By failing to consider the population of Americans that owned telephones in 1948, the researchers conducting the telephone survey committed non-representative sample. As a result, they received severely skewed response data.

Instead of distributing a more effective survey to a sample that more accurately represented the population of the United States at the time, the researchers ended up with inaccurate and unrepresentative insights.

The conductors of the survey were confident that Dewey would win the presidential race with ease, while in the end, it was Truman that ended up becoming the leader of the free world.

Hence the outcome was a complete disaster.