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Impact of Outliers on the Range
Although the range is easy to calculate, it can be highly misleading when outliers are present. A single extreme score can drastically increase the range, creating the false impression that the overall distribution has high variability when most scores are actually grouped closely together.
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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.
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In psychological research, what is the primary reason the range can be a highly misleading measure of variability for a set of scores?
If a researcher observes a very large range in a dataset, they can safely conclude that the majority of the individual scores are widely dispersed from one another.
A psychology researcher is evaluating the variability of three different groups of scores on a memory task (scored from to ). Match each dataset to the statement that best analyzes how the range represents the dispersion of that specific group.
A psychology researcher is evaluating how accurately the range represents the typical variability of scores in different datasets. Arrange these research outcomes in order from the most representative (least misleading) range to the most misleading (least representative) range.
True or False: The range is often a misleading measure of variability because its value can be drastically increased by the presence of even a single extreme score.
A psychology researcher collects anxiety scores (on a scale of to ) for a small group: , , , , and . Although the calculated range is (), why does this value provide a misleading description of the variability in this group?
A psychology researcher collects scores from an anxiety scale (scored 0–100) for five participants: 20, 22, 24, 26, and 28. If a sixth participant is added to the study with an extreme score of 100, the new range for this dataset is _____.
A psychology researcher is evaluating exam scores across three different sections. Match each exam score dataset to the statement that describes the impact of its outlier status on the range.
A researcher calculates the range for exam scores where most students scored between and , but one student scored . The researcher notes that the range increases from to . In this scenario, the score of is acting as an _____ which drastically inflates the range.
A researcher wants to evaluate how misleading the range is as a measure of variability in different datasets of exam scores. Order these scenarios from the least misleading range (most representative of the overall variability) to the most misleading range (least representative of the overall variability due to outlier impact).