Mean Grouped Data

Which of the following values are correct based on the frequency table shown?

• n = 35 ; Σfx­_m = 3358

• n = 40 ; Σfx­_m = 3358

• n = 35 ; Σfx­_m = 3385

• n = 40 ; Σfx­_m = 3385

Which of the following is true about the frequency table shown?

• n = 50 ; Σfx­_m = 3895

• n = 55 ; Σfx­_m = 3895

• n = 50 ; Σfx­_m = 3890

• n = 55 ; Σfx­_m = 3890

Estimate the mean weight

• 63.5

• 65

• 67.2

• 70.1

• 30

• 40

• 50

• 60

The value of X in the table is

• 141

• 145.5

• 150

• 216

The table below recorded the number of newspapers sold by different stores in a week. Determine the mean of the number of newspapers.

• 4.58

• 6.56

• 30

• 44.58

The table shows data on the heights of plants.

The midpoints have been multiplied by the frequencies, and two totals have been found.

What calculation is now done to find an estimate for the mean?

Answer explanation

The total of the final column should be divided by the total frequency (the total number of items in the data)

The table shows times taken by pupils to complete a task.

Some of the midpoints and calculations have been done for you.

Complete the calculations and find an estimate for the mean.

Mathematical Equivalence

ON

The table shows weights of a sample of children.

Calculate an estimate for the mean weight.

Give your answer correct to 1 decimal place.

Mathematical Equivalence

OFF

• The student's answer is too small.

• The student's answer is correct.

• The student's answer is too big.

Answer explanation

The student used the highest value for each group (instead of the midpoint) so this will make their answer too large.