5, 5, 5, 5 এই তথ্য সারির পরিসর কত?

The mean deviation about the mean of the following data is?

The standard deviation of the data 6, 5, 9, 13, 12, 8, 10 is

The median and S.D of a distribution are 20 and 4 respectively. If each item is increased by 2, the new median are S.D are:

A game of chance consists of spinning an arrow which is equally likely to come to rest pointing to one of the number $1,2,3,........,12$ as shown in figure.
What is the probability that it will point to multiple of $4$ ?