Statistics Test...

The class mark of the class 90-120 is 

For drawing a frequency polygon of a continuous frequency distribution, we plot the points whose ordinates are the frequencies of the respective classes and abscissae are the:

According to above histogram, which group has the maximum number of workers?

What is the sum of the frequencies of the intervals 40-50 and 50-60 ?

How many students watched TV for less than 4 hours?

What is the difference of frequencies of the intervals  30-40 and 40-50 ?

According to above histogram, how many workers earn less than $$Rs. 850$$?

If the class intervals in a frequency distribution are $$(72 - 73.9), (74 - 75.9), (76 - 77.9), (78 - 79.9)$$ etc., then the mid-point of the class $$(74 - 75.9)$$ is

The upper limit of $$5 -12.5$$ is?