Abstract Process capability indices C p and C pk are widely used in statistical quality control to assess the capability of a process. These indices are defined, based on the assumption that the quality characteristic follows a normal distribution. In this paper two new capability indices are...

We introduce a new distribution useful for positively skewed dataset with heavy tails and refer to it as the “Wright distribution”. Properties involving moments, skewness and kurtosis are studied. Simulation study and derivation of the density function using fractional calculus method are...

This paper presents gamma stochastic volatility models and investigates its distributional and time series properties. The parameter estimators obtained by the method of moments are shown analytically to be consistent and asymptotically normal. The simulation results indicate that the estimators...