For 95% confidence limits true is :
Ans. is 'a' i.e.1.95 of standard error of mean [Ref: Park 20/e, p 751 (18/e, p647, 17/e p613, 16/e, p 595)Jx +/- 1 - (area b/w 1 S.D on either = 68% confidence limits side of mean)x +/- 2 - (S.D.) =95.4%x +/- 3 - (S.D.) =97.7%
1.95 of standard error of mean
Reduces 95% of values
2.95 of standard error of mean
Normal distribution+-2.5 S.D.
Measures of Central Tendency and Distribution