Two Tailed Tests
A two tailed test is generally used in statistical work as tests of significance for illustration, if a complaint lodged by the client is about a product not meeting specific specifications that is the item will generate a complaint if its measurements are above the upper tolerance limit or below the lower tolerance limit
NB: Alternative hypothesis is generally rejected if the standardized value of the sample mean lies beyond the tolerance limits as 15 centimeter and 17 ½ centimeter.