A Researcher Records the Sound (In Decibels)during a Series of Lessons

question 48

Multiple Choice

A researcher records the sound (in decibels) during a series of lessons taught by a substitute teacher at a local elementary school.In his study,he found that the sound was 80 ± 6 (M ± SD) decibels.Assuming the data are normally distributed,which of the following is an appropriate conclusion?

• A) At least 68% of classes were between 76 and 84 decibels.
• B) At least 5% of classes were louder than 68 decibels.
• C) At least 95% of classes were between 68 and 92 decibels.
• D) All of these.

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