# Question: Thirty automobiles were tested for fuel efficiency in miles per

Thirty automobiles were tested for fuel efficiency (in miles per gallon). This frequency distribution was obtained.

Class boundaries Frequency

7.5–12.5 ..........3

12.5–17.5 ...........5

17.5–22.5 .........15

22.5–27.5 ...........5

27.5–32.5 ...........2

Find the variance and standard deviation.

Class boundaries Frequency

7.5–12.5 ..........3

12.5–17.5 ...........5

17.5–22.5 .........15

22.5–27.5 ...........5

27.5–32.5 ...........2

Find the variance and standard deviation.

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