review the topic and then answer the following question: XYZ offers dental insurance to its employees. A recent study of the plan shows the annual cost per employee followed the normal distribution with a mean of $1280 and a standard deviation of $420 per year. For your answers round to two significant digits. What portion of the employees cost more than $1,500 per year for dental expenses? Give the answer in percentage rounded to the whole number. What is the z-score? For a comparison, you decide to look at the national study of the dental plan with a mean and a standard deviation. Would the two samples (XYZ and national) be considered independent or dependent? Explain