Simply Stat Software (SSS) is sold in 52 computer supply stores. The following frequency distribution gives a breakdown of the number of sales by the stores.

Number of SSS soldNumber of stores W/this number of sales (Frequency)

5 - 92

10 - 144

15 - 1911

20 - 2425

25 - 297

30 - 343

Which one of the following statements is true?

• The cumulative relative frequency for the modal class is 0.808.
• The mode is 25 stores.
• The class width is 4.
• The median is 8.67stores.
• All the class widths are not the same.