Statistics Test...

The blood groups of 30 students are recorded as follows:
$$A, B, O, A, AB, O, A, O, B, A, O, B, A, AB, B, A,$$

In the class intervals $$10-20, 20-30$$, the number $$20$$ is included in:

Let $$m$$ be the mid-point and $$l$$ be the upper class limit of a class in a continuous frequency distribution. The lower class limit of the class is:

In a frequency distribution, the mid value of a class is $$10$$ and the width of the class is $$6$$. The lower limit of the class is:

A grouped frequency table with class intervals of equal sizes using $$250-270$$ ($$270$$ not included in this interval) as one of the class interval is constructed for the following data :
$$268, 220, 368, 258, 242, 310, 272, 342,$$
$$310, 290, 300, 320, 319, 304, 402, 318,$$
$$406, 292, 354, 278, 210, 240, 330, 316,$$
$$406, 215, 258, 236.$$
The frequency of the class $$310-330$$ is:

To draw a histogram to represent the following frequency distribution:

A grouped frequency distribution table with classes of equal sizes using $$63-72$$ $$(72$$ included$$)$$ as one of the class is constructed for the following data:
$$30, 32, 45, 54, 74, 78, 108, 112, 66, 76, 88,\\
40, 14, 20, 15, 35, 44, 66, 75, 84, 95, 96,\\
102, 110, 88, 74, 112, 14, 34, 44$$
The number of classes in the distribution will be:

The width of each of five continuous classes in a frequency distribution is $$5$$ and the lower class-limit of the lowest class is $$10$$. The upper class-limit of the highest class is:

The class marks of a frequency distribution are given as follows: $$15, 20, 25, ...$$
The class corresponding to the class mark $$20$$ is:

If the mean of the observations:
$$x, x + 3, x + 5, x + 7, x + 10$$ is $$9$$, the mean of the last three observations is