If the classes of a frequency distribution are 1 - 10, 11 - 20, 21 - 30, ….., 61 - 70, then the upper limit of the class 11 - 20 is

1. 20

2. 21

3. 19.5

4. 20.5

In a grouped frequency distribution, the mid-values of the classes are used to measure which of the following central tendency?

1. median

2. mode

3. mean

4. all of these

Construction of a cumulative frequency distribution table is useful in determining the

1. mean

2. median

3. mode

4. all the three measures

Construct the following frequency distribution :

The upper limit of the median class is

1. 17

2. 17.5

3. 18

4. 18.5