Question

The given graph represents the monthly salaries (in ₹) of workers of a factory.

Using graph answer the following:

1. the total number of workers. 
2. the median class. 
3. the lower-quartile class. 
4. number of workers having monthly salary more than or equal to ₹6,000 but less than ₹10,000.

Answer 1

(a) The highest point is at 75 workers. Hence, the total number of workers is 75.

(b) Since, n = 75 (odd)

`"Median" = ((n + 1)/2)^(th) "observation"`

= `((75 + 1)/2)^(th) "observation"`

= 38^th observation

The cumulative frequency reaches 35 at ₹6,000 and 55 at ₹8,000.

Therefore, the median class is ₹6,000 to ₹8,000

(c) The lower-quartle class = `((n + 1)/4)^(th) "observation"`

=`((75 + 1)/4)^(th) "observation"`

= 19^th observation

The cumulative frequency reaches 20 at ₹4,000. Therefore, the lower-quartile class is ₹2,000 to 4,000.

(d) At ₹6,000 there are 35 workers and at 10,000 there are 70 workers.

Therefore, the number of workers in this salary range 70 − 35 = 35.