The cumulative frequency curve shows the distribution of the wages per week of 80 workers in a factory.

1. (a)

   Use the curve to estimate

   1. (i)

      the median wages per week,

      Answer $$ ...

   2. (ii)

      the interquartile range of the wages per week.

      Answer $$ ...

2. (b)

   In June 2024, the average wages per week of factory workers in Singapore was $540.
   Calculate the percentage of the workers in the factory who earned more than this average.

   Answer ... %

3. (c)

   Find the number of workers who earned between $460 and $800.

   Answer ...

4. (d)

   The factory employed more workers and paid them not more than $650 per week.
   Find the additional number of workers employed if the probability of choosing a worker who earned not more than $650 is 11/15.

   Answer ...