4. NOTE 1. In this question you will use articial "data" for a case where we know the true mean and variance of the distribution in question. This is never the case for a \"real-life\" statistical procedure, for which the true mean and the true variance are unknown (and for which our aim is to attempt to estimate them andfor test hypotheses about them). The purpose of doing this question is to give you condence in the procedures we use, by considering a case where we can check that our procedures "work". In question 5 below you will consider real data from an experiment where we do not know the true mean and variance: this question is therefore typical of a real statistical procedure. NOTE 2. The artificial "data" are to be derived from the attached chart of the \"standard normal distribution\