The numbers 4 and 9 have frequencies x and (x - 1) respectively. If their arithmetic mean is 6, then what is the value of x ?
2
3
4
5
What is the sum of the last five coefficients in the expansion of (1 + x)9 when it is expanded in ascending powers of x ?
256
512
1024
2048
The arithmetic mean of 100 observations is 40. Later, it was found that an observation ‘53’ was wrongly read as ‘83’. What is the correct arithmetic mean ?
39.8
39.7
39.6
39.5
If ∑xi = 20, ∑xi2 = 200 and n = 10 for an observed variable x, then what is the coefficient of variation ?
80
100
150
200