Frequency Table or Histogram

What is the cumulative frequency of the third class?

• f_{1 +} f₂ + f₃ = 5 + 8 + 6 = 19

• f_{1 +} f₂ + f₃ = 5 + 6 + 10 = 21

• f_{1 +} f₂ + f₃ = 1 + 6 + 11 = 18

Observe the frequency distribution:

Estimate the class width.

• 11

• 10

• 25

• 19.5

Observe the frequency distribution:

Estimate the first class boundary (the "lower" class boundary of the first class).

• 19.5

• 20

• 25

• 20.5

Observe the frequency distribution:

Estimate the relative frequency of the fourth class.

• 69

• 5.3

• 0.189 or 18.9%

• 0.54 or 54%

Observe the frequency distribution:

Estimate the midpoint of the seventh class.

• 86

• 91

• 96

• 96.5

• 85.5

Observe the frequency distribution:

Estimate the class boundaries.

• 20, 31, 42, 53, 64, 75, 86, 96

• 20, 31, 42, 53, 64, 75, 86

• 19.5, 30.5, 41.5, 52.5, 63.5, 74.5, 85.5, 96.5

• 30, 41, 52, 63, 74, 85, 96

To construct a histogram, we have to estimate ________ or _______ to label the horizontal axis.

• midpoints - class boundaries

• lower class limits - upper class limits

• frequencies - data entries

• colours - numbers

Observe the histogram and choose the frequency distribution that corresponds to it.

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• 

The following data set shows the minutes spent on internet by 50 internet users. Use seven classes to construct a frequency distribution. What's the class width?

• 11

• 12

• 7

• 86

The following data set shows the minutes spent on internet by 50 internet users. Use the class width from the previous question to find the lower class limits if the first lower class limit is the minimum value of the data set.

• 7, 7, 11, 17, 19, 20, ...

• 6.5, 18.5, 30.5, 42.5, 54.5, 66.5, 78.5

• 12.5, 24.5, 36.5, 48.5, 60.5, 72.5

• 7, 19, 31, 43, 55, 67, 79