An estimator T_n of θ is said to be more efficient than any other estimator T ^⋅_(n) of θ if and only if

If X is a normal variate with mean 20 and variance 64, the probability that X lies between 12 and 32 is

If X is a normal variate representing the income in Rs. per day with mean=50 and S.D=10. If the number of workers in a factory is 1200, then the number of workers having income more than Rs. 62.00 =0.3849 where Z is a standard normal variate)

If X is a random variable, E(e ^tX ) is known as