(14. A school dentist regularly inspects the teeth of children in their last year at primary school. She keeps records of the number of decayed teeth for these eieven year old children in her area. Over a number of years, she has found that the number of decayed teeth was normally distributed with mean 3.4 and standard deviation 2.1. She visits just one middle school in her rounds. The class of 23 twelve - year olds at that school have mean of 3.0 decayed teeth. At the 5% signicance level, is there any difference between this group and her usual eleven year old patients? a} State the null and alternative hypothesis (2 mark} b} Is this a one- or two- tailed test? [1 mark} c) What is the decision rule? [3 marks} d) What is the value of the test statistics? (5 marks) e) What is your decision regarding Ho? (1 mark) f) Interpret the result of the hypothesis testing