To develop interval estimate of any parameter of population, value which is added or subtracted from point estimate is classified as Select ane: a margin of efficiency O b. margin of biasedness c. margin of error O d. margin of consistency For a normal curve, the mean, median and mode are Select one: a all equal O b. all different O c. always the largest and the mode always the smallest O d. all zero Considering sample statistic, if mean of sampling distribution is equal to population mean then sample statistic is classified as Select one: a unbiased estimator O b. biased estimator c. interval estimator O d. hypothesis estimator The lifetime X of an alkaline battery is exponentially distributed with A = 0.02 per hour. What are the mean and standard deviation of the battery's lifetime? Select one: O a 25 O b. 1 c. 002 O d. 50