If 4,5,6,6,6,6,6,6,6,7 be a random sample from a Poisson population with parameter λ, then an unbiased estimate of λ is :
The coefficient of correlation between two variables X and Y is 0.48. The covariance is 36. The variance of X is 16. The standard deviation of Y is :
A random sample of size n is drawn from a population of size N by SRSWOR method. Then the standard error of sample mean will be zero if n is
Which type of sampling is one where only the first sample unit is selected at random and the remaining units are automatically selected in a definitesequence at equal spacing from one another. It is :
