1.1. A fjord is a deep and narrow part of a sea with steep land on three sides.

Emily is investigating the length of fjords in Norway. She collects some data from the internet and puts the data into a grouped frequency table.

The grouped frequency table below shows information about the results she collected.

(Source: https://en.wikipedia.org/wiki/List_of_Norwegian_fjords)

Work out the number of fjords that have a length of at least 100km.

1.2. (i) Calculate an estimate of the mean length of these fjords.
Give your answer to 1 decimal place.

......................... km (3)

(ii) Explain why your answer to part (b)(i) is only an estimate.

(1)

(iii) How could Emily have improved the accuracy of her answer to part (b)(i)?

(1)

1.3. Emily plans to use a frequency polygon to represent the lengths of the fjords.

Discuss whether or not a frequency polygon would be an appropriate diagram to use.