A group of researchers is trying to find a way to prevent the extinction of whale sharks die to a virus contaminating water that only affects whales. They want to strengthen the immunity of the whales by injecting a special serum into their body. To accomplish that they get a sample of 50 whales. Test the hypothesis that the average whale getting the serum is less than 20. Use 5% of significance. Solve for the test-statistic and P-value. Use 3 decimal places for all answers and make a general conclusion for the hypothesis.