Correctly you must use Excel and show your workings . 1. From a survey of co-workers, you find that 55% of 180 have already received this year's flu vaccine. An approximate 95% confidence interval is (0.477, 0.623). a. How would the confidence interval change if the sample size had been 720 instead of 180? b. How would the confidence interval change if the confidence level had been 90% instead of 95%? c. How would the confidence interval change if the confidence level had been 98% instead of 95%