Provide an original example of some practical case where we can use the normal distribution (e.g., IQ scores follow a normal distribution of probabilities with a mean IQ of 100 and a standard deviation of 15 IQ points.). Assign your numbers for mean and standard deviation . Make sure is about four times bigger than . Then select any number "a" below or above mean , but not too far from . The difference (a - ) should be less than 3. For example, = 80, = 20, a = 90 (or a = 75). Find following two probabilities: 1) P(x < a) 2) P(x > a) Use the formula z = (a - )/ to calculate your z-value. Please refer to the Appendix Table for the Standard Normal Distribution within the eText to find the desired probabilities. Hint: To find P(x>a) use formula: P(x>a) = 1 - P(x