Assume that a random variable under consideration has a density curve. Answer the following questionsa) The area under the density curve that lies to the left of 10 is 0.645. What percentage of all possible observations of the variable are at least 10? (2 marks)b) Suppose that the density curve has an area of 0.361 to the left of 12 and an area of 0.428 to the right of 14. What is the size of the area between 12 and 14? (2 marks)c) Assume that the distribution of the random variable is standard normal. Determine the -scores that mark the 89^thpercentile and the upper 0.3% of the standard normal distribution. (2 marks)