Finding and Eliminating Sources of Error on the GED Science Test

By Murray Shukyn, Achim K. Krull

You will be expected to find sources of error for the GED Science test. If scientists were perfect, then every experiment would prove the hypothesis and be reproducible by any other scientist at any time. Unfortunately, scientists are human, and errors may creep into the observations, leading to results that can’t be reproduced.

In a proper and valid experiment, all errors and potential errors should be documented and analyzed to help researchers in the future reproduce the experiments without repeating the errors. Errors are generally divided into two groups:

  • Systematic errors: Flaws in the experimental procedure from faulty calibration of measuring instruments, faulty use or reading of an instrument (parallax error), using faulty equipment, or using equipment that was designed for some other purpose. Properly documenting systematic errors helps future researchers avoid them.

    Systematic errors are typically one-sided errors (consistently high or consistently low).

  • Random errors: These arise when those conducting the experiment have trouble reading measurements; for example, when a needle moves when taking a reading or a needle is between two lines on a meter. Such errors affect measurement precision and can be reduced through repeating the measurement or refining the measurement method or technique.

    Random errors are typically two-sided errors (results fluctuate above and below the true or accepted value).

  1. Why is documenting errors in experiments or studies so important?

    • (A) It enables researchers to repeat the experiment without repeating the errors.

    • (B) Any error can affect the conclusions reached.

    • (C) Errors may shed light on the reliability of the data.

    • (D) All of the above.

  2. Why is the documentation of errors in an experiment important for consumers, as well as for scientists?

    • (A) Attorneys can use the information to sue drug companies.

    • (B) You may want to become a scientist one day.

    • (C) Errors reflect the reliability of evidence about consumer products.

    • (D) Consumers may want to conduct the studies themselves.

  3. Scientists record the procedures they followed to conduct an experiment for which of the following reasons?

    • (A) to enable others to evaluate the experiment and its conclusions

    • (B) to inform the scientific community of recent discoveries

    • (C) to document their accomplishments

    • (D) to encourage other scientists to reproduce the experiment

Check your answers:

  1. All the answer choices, Choice (D), explain why documenting errors in an experiment is important.

  2. Scientists aren’t the only ones who need to evaluate the reliability of data from studies. Consumers, Choice (C), can also benefit from knowing about errors in studies.

  3. Disclosing the procedures followed enables others to evaluate the experiment and its conclusions, Choice (A).