There are two startups in ecommerce sector struggling to acquire the market. Following data is for Mean and Standard Deviation of billing amount of bought items per month on their website.Startup | A | BNo. of customers/Month | 40 | 30Mean billing amount | $\displaystyle 2,500 |$2,200SD of billing amount | $\displaystyle 10 |$11Which startup has a better consistency in terms of sales numbers?

If the range of $\displaystyle 28, 22, 40, 20, 15, 50$ is

If the S.D. of the $\displaystyle 1^{st}$ $\displaystyle n$ natural numbers is $\displaystyle \sqrt{30}$ then the value of $\displaystyle n$ is

If the variance of $\displaystyle 5, 7, 9$ and $\displaystyle 11$ is $\displaystyle 4$, then the coefficient of variation is:

A helicopter flies from A to B at the rate of 500 km/hr. and comes back at the rate 700 km/hr. The average speed of the helicopter is

If Arithmetic Mean (A.M.) and Geometric Mean (G.M.) of two numbers are 6.50 and 6 respectively, then the two numbers are

Which of the following is not a method of dispersion?