indicate that the cloth should have a mean breaking strength of 30kg and a standard deviation of 3.5kg. The distribution of the breaking strength is known to be normal.
A sample of 49 pieces of cloth reveals a sample mean breaking strength of 29.3kg.
Is there evidence that the machine is not meeting the manufacturer's specifications for mean breaking strength? Use a 5% level of significance and the critical value approach. Ensure that you clearly state your hypotheses, show ALL steps, ALL your working AND interpret your conclusion in context of this question.