Chapter 6 Section F: Choosing the Sample Interval

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Chapter 6 Section F Choosing the Sample Interval

• Emma Hetico, Molly Ellsworth, Esther Tree,
  Xiangyi Tan

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Time Sampling

• Researchers use time sampling to ease observation
  and record in time intervals rather than CR
  (impractical)
• Must balance the recording duration with quality
  of measurement

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What is best for your experiment?

• Size of sample interval used in time sampling
  will depend on how many categories are being
  recorded as well as nature of behavior
• Shorter Sample
• More accurate- specific time period
• Less reliable- cant look at the broad picture

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Lab Observations

• Generally use a range from 10 s to 1 min
• Intervals of 15s, 20s, 30 s

Field Observations

• Longer recording sessions

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Steps to Find an Ideal Time

• Do initial continuous recording
• Record data in intervals
• Either record on tape
• Have multiple observers measuring each interval
• Calculate discrepancy between Continuous
  Recording (CR) and time intervals

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Figure 6.5

• CR is used as pilot sample (standard)
• 10s -20s- the discrepancy is less than 10
• Very close to CR meaning it is reliable data
• 30s -120s- high discrepancy
• Not all data is collected meaning it is not
  reliable data