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Excluding Outliers
When preliminary analyses reveal extreme outliers resulting from data entry errors, misunderstandings, or a lack of participant effort, researchers may justify excluding these anomalous data points. However, strict methodological standards require researchers to apply exclusion criteria consistently, retain the original data without permanently deleting it, and transparently report both the number of exclusions and the specific reasons for their removal.
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Research Methods in Psychology - 4th American Edition @ KPU
Related
Excluding Outliers
Handling Valid Extreme Outliers
Example of an Outlier
Sensitivity of the Mean to Outliers
Defining Outliers using z Scores
Reaction Time Outlier Example
Impact of Outliers on the Range
Identifying Outliers Using z Scores
Handling Outliers
What term is used to describe an extreme score that falls significantly above or below the rest of the scores within a distribution?
In psychological research, an outlier in a dataset always indicates that an error occurred during data collection, such as an equipment malfunction or participant misunderstanding.
In psychological research, outliers can arise from various sources. Match each research scenario with the most likely reason for the extreme score described.
A researcher identifies a score in a dataset that falls significantly below the rest of the distribution. Arrange the following steps in the logical analytical sequence used to investigate and address this extreme value.
You are constructing a research protocol for a study on the cognitive effects of extreme stress. To ensure that your final dataset can systematically distinguish between genuine cases of 'stress resilience' (valid outliers) and 'task confusion' (measurement errors), which design element should you integrate into your data-collection phase?
Sexual Partners Survey Outlier Example
Outlier in Beck Depression Inventory Scores
A researcher is evaluating a dataset where a single participant's score is , while all other scores are between and . After confirming the participant understood the task perfectly and no errors occurred, the researcher decides to retain the score. This decision reflects a judgment that the extreme value is a(n) _____ which, despite its potential to skew the mean, represents a genuine and valid case within the study.
A researcher measures anxiety in 50 participants and finds that 49 scores fall between 20 and 45, but one participant scores 95. This extreme value, which may reflect a genuinely anxious individual or a data collection error, is called a(n) _____.
A researcher administering a depression inventory notices one participant scored far higher than the rest of the sample. If the researcher confirms this participant is indeed clinically depressed and no data entry or equipment errors occurred, this extreme score is no longer considered an outlier.
Match each description of a research scenario that produces an extreme score with its corresponding source of outlier.
When conducting data cleaning on a newly collected psychological dataset, order the stages a researcher should follow to systematically identify and categorize an extreme score.
Define what an outlier is in the context of a dataset's distribution, and describe the two broad categories of sources that can produce these extreme scores in psychological research.
Based on the provided context, diagnose the nature of this student's extreme score. Is this outlier a result of an error, or does it represent a genuine case? Explain your reasoning.
A researcher asks participants to report their age in years. Most responses range from to . One participant enters . Apply the definition of an outlier to explain what this value represents and identify the most likely reason for this extreme score based on common sources of outliers.
Which of the following best describes an outlier?
Because outliers are extreme scores that fall significantly outside the rest of a distribution, a researcher should always assume they are the result of equipment malfunctions, participant misunderstandings, or data entry errors.
An outlier is an extreme score that falls significantly above or below the rest of the distribution. Match each research scenario below to the most likely source of the outlier it describes.
While analyzing a distribution of questionnaire scores, a researcher spots an extreme score that falls significantly above the rest. Upon examining the raw data, the researcher notices the participant selected 'Strongly Agree' for every item, including directly opposing statements such as 'I am always anxious' and 'I am always calm.' This contradictory evidence indicates that the extreme score is not a genuine case, but rather an outlier resulting from a participant ____.
A researcher needs to judge whether a suspicious data point should be included in their analysis. Arrange the following steps in the most logical sequence to systematically evaluate the source of this outlier, from initial observation to final judgment.
While an outlier can result from mistakes, it can also represent a 'genuine case' on the variable being measured. Which of the following is an example of a genuine case?
When a researcher identifies an extreme score in a distribution, why is it important to carefully consider its source rather than immediately discarding it?
During a study on early language acquisition, a researcher finds that 49 out of 50 toddlers have a vocabulary of 20 to 50 words, while one toddler has a verified vocabulary of over 200 words. Because this unusually high score represents a genuine case rather than an equipment malfunction or researcher error, it should not be classified as an outlier.
Researchers must carefully break down the context of extreme scores to identify their source. Match each piece of analytical evidence to the specific source of the outlier it most strongly suggests.
A cognitive psychologist notices an extreme score in a reaction time distribution that falls significantly below the rest of the scores, indicating an incredibly fast response. Without checking the laboratory logs, the researcher immediately deletes the score, stating, 'Extreme outliers are always the result of equipment malfunctions or participant misunderstandings, so this data point is invalid.' How should this researcher's decision be evaluated?
Learn After
According to strict methodological standards, which of the following is a requirement when a researcher decides to exclude extreme data points from a dataset?
Match each methodological standard for handling anomalous data with the correct description of its application in a psychology study.
A psychology researcher identifies an extreme outlier in their dataset that resulted from a clear data entry error. True or False: To follow strict methodological standards, the researcher should permanently delete this participant's row from the original master spreadsheet to ensure that future analyses of the raw data remain accurate.
A psychology researcher identifies several anomalous data points during preliminary analysis. To adhere to strict methodological standards when excluding these outliers, in what order should the following steps be performed?
Which of the following best explains the rationale for transparently reporting both the number of exclusions and the specific reasons for removing outliers in a psychology study?
A researcher identifies extreme outliers in their dataset but only excludes those that contradict the study's hypothesis while keeping those that support it. When evaluating the validity of this study, a critic would conclude that the researcher failed to apply their exclusion criteria _____.
According to strict methodological standards in psychology research, a researcher who excludes outliers from their analysis must transparently report both the specific reasons for the removal and the total _____ of data points that were excluded.
A developmental psychology researcher discovers that a participant's recorded age is 190 years due to a typing error (the decimal point was missed for a 19-month-old). To correct this, the researcher permanently deletes this participant's row from the master database and runs the analysis. True or False: This action follows strict methodological standards for excluding outliers.
Match each scenario of handling data in a psychology study with the specific methodological standard for excluding outliers it illustrates.
A psychology researcher is preparing to analyze their experimental data. Arrange the steps the researcher should take to handle and report outliers, from first to last, in accordance with strict methodological standards.
According to strict methodological standards in psychology research, what are the three requirements that researchers must follow when they choose to exclude extreme outliers, and what are the three typical causes of these outliers mentioned in the research methods text?
Explain how the researcher should handle these outliers in accordance with the three strict methodological standards of data exclusion, demonstrating your understanding of how each standard applies to this study.
A psychology researcher finds an extreme outlier caused by a participant's misunderstanding of the instructions. Apply the strict methodological standards of outlier exclusion to describe what the researcher should do with their raw data file and what details they must include in their final research report regarding this outlier.