A coin is tossed repeatedly until a head appears. If 'p' be the probability of getting a head in any toss and x be the number of tosses required to get the first head then which of the following statement is true:
If the regression line of Y on X is Y =30 0.9X and the standard deviations are Sx = 2 and Sy = 9, then the value of the correlation coefficient rxy is :
Which of the following is a method of collection of primary data?
