Grouped Frequency Table

Which is the modal class?

• 140 ≤ h < 150

• 150 ≤ h < 160

• 160 ≤ h < 170

• 170 ≤ h < 180

For this data, how many data points are there?

• 4 children

• 51 children

• 180 cm

• 140 cm

Estimate the mean height of these 25 trees (using your calculator)

• 100cm

• 116cm

• 118cm

• 119cm

Estimate the mean height of these 123 students (using your calculator)

• 166cm

• 167cm

• 168cm

• 169cm

Choose the correct frequency distribution table for the data of annual attendance of 40 students in standard IX, using the class intervals 155 - 165, 165 - 175 and so on. Annual attendance: 171, 183, 192, 168, 156, 162, 158, 159, 178, 192, 186, 173, 169, 162, 182, 191, 194, 169, 174, 158, 186, 174, 176, 181, 179, 193, 164, 176, 159, 158, 166, 168, 187, 188, 192, 194, 166, 173, 179, 187

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Answer explanation

Estimate the mean time 116 students spent procrastinating in Mr Chang's class (using your calculator)

• 21.1 min

• 22.1 min

• 23.1 min

• 24.1 min

Prices of vehicles sold last month at a local dealership are going to be tallied into these classes. If a car was sold for $24,000 which category would the tally belong?

• $15,000 up to $18,000

• $21,000 up to $24,000

• $24,000 up to $27,000

• $27,000 up to $30,000

How many classes are there in this table?

• 51

• 4

• 10

• 2

To estimate the mean, we should use

• each class' lower bound

• each class' upper bound

• each class

• each class' middle value

Why can we only estimate the mean for this given data?

• There's no need being precise

• We don't have the raw data

• Mr Chang is lazy

• We may have counted the students incorrectly