Tales by Dots and Lines: common misconceptions

If your child says… “The biggest pile gives the mean.”

Ask together

Are there enough chickpeas to give every pile 4?

What’s true

The mean shares the whole collection equally across all piles.

If your child says… “The mean must be one of the dots.”

Ask together

When you uncover the mean marker, is there an observation above it?

What’s true

The mean can differ from every recorded value.

If your child says… “I only need to count the newly added value.”

Ask together

Where have you allowed for replacing the original 2?

What’s true

Both the correction and the extra record affect the calculation.

If your child says… “Only the two visible dots count.”

Ask together

How many dots will the completed plot contain?

What’s true

The required total includes the missing observation.

If your child says… “February is highest, so 50 is the change.”

Ask together

How far apart are January's and February's readings?

What’s true

A change compares two readings rather than using either reading alone.

If your child says… “The monthly average tells us it rained every day.”

Ask together

Where does this graph give a separate reading for each day?

What’s true

A monthly summary does not provide each day's rainfall.

If your child says… “Each cell means a whole hour.”

Ask together

How much time passes between neighbouring boundary labels?

What’s true

The stated time scale determines each cell's duration.

If your child says… “Sunset at 18:30 means 18 hours 30 minutes of daylight.”

Ask together

Does daylight begin at midnight or at the sunrise reading?

What’s true

A clock reading marks an event, while duration measures the time between events.