The National Association of Colleges and Employers in the U.S. conducts surveys of salary offers to new college graduates and publishes the results in Salary Survey. For comparing the salaries to computer engineering graduates from the first quarter 2005 with the first quarter 2006 we will use the data from random samples from each quarter displayed below: 3 2005 2006 mean x $51900 $54200 stdev s $1050 $1200 sample size n 100 100 (a) (10 marks) Do the data provide sufficient evidence that the mean salary offered to computer engineering graduates increased from the first quarter in 2005 to the first quarter in 2006? (b) (8 marks) Calculate a 95% confidence interval for the difference in mean salary for new graduates in computer engineering for the first quarter in the years 2005 and 2006. Give a complete interpretation of the result.