Can anyone help with a solution to this question?

Question 1 a) The average incomeimonth of a Spanish worker is known to be equivalent E5,000 with standard deviation f11,250. A sample of 50 workers is taken and their average income calculated. i) What is the probability distribution of this sample mean? ii) What is the probability of the sample mean being over \&5,500? iii) What is the probability of the sample mean being below \&4,500? iv) If the sample size were 10, why could you not use the same methods to find the answers to (i)-(iii)? (20 marks) b) The age of adults in Spain was estimated by considering a sample with sample mean equal to 30. standard deviation equal to 8. and sample size equal to 40. Calculate the 99% confidence interval estimate of the true mean of age of adults in Spain. If the sample size was 15. show and cornment on how the method of calculation and confidence interval were altered. (13 marks)