In a monthly test, the marks obtained in Mathematics by 16 students of a class are as follows :

0, 0, 2, 2, 3, 3, 3, 4, 5, 5, 5, 5, 6, 6, 7, 8

The arithmetic mean of the marks obtained is :

1. 3

2. 4

3. 5

4. 6

Out of 100 numbers, 20 were 4s, 40 were 5s, 30 were 6s and the remaining were 7s. The mean of the numbers is :

1. 5.3

2. 5.4

3. 6.1

4. 6.5

If the mean of 7 observations is 43 and each observation is increased by 7, then what will be the new mean?

1. 36

2. 43

3. 44

4. 50

While computing the mean of grouped data, we assume that the frequencies are :

1. evenly distributed over all the classes

2. centred at the class marks of the classes

3. centred at the upper limits of the classes

4. centred at the lower limits of the classes