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A. Directions Solve the following problems 1, In Statistics and Probability examination, the average grade was 74 and the standard deviation was 7. I1 11.9% of the class is given X's scores, and the grades follow a normal distribution, what is the lowest possible score X and the highest possible score Y? 2. The average life expectancy of a certain refrigerator is 10 years, with a standard deviation of 2 years. The manufacturer replaces the purchased refrigerator if the buyer finds that the product has a problem or defect. The replacement is free of charge as long as it is covered by the warranty. If the manufacturer is willing to replace only 3% of the refrigerators that are found to be defective, how long should the given warranty be? Assume that the lifespan of the refrigerators follows a normal distribution 3 An employee's weekly income in a certain online job follows a normal distribution with a mean of PHP1,000 and a standard deviation of PHP100 What is the z value for the income of: a. person who ears PHP1,100 per week? b person who earns PHP 900 per week