2. Estimation and Confidence Interval 1. A simple random sample of 36 20-year-old young adults residing in Adelaide were obtained and their body weights (in kg) were recorded in the following table. As- sume that the weights of individuals are normally distributed and the standared deviation is 7.2 kg based on other similar studies. What is the estimated aver- age weight for all 20-year-old young adults residing in Adelaide? (Give the 95% confidence interval.) 67.8 68.4 59.2 56.9 63.9 62.2 55.6 72.9 62.6 67.1 73.4 63.7 57.7 66.7 61.7 55.5 49.3 72.9 49.9 56.5 71.2 59.1 64.3 64.0 55.9 51.3 53.7 56.0 76.7 76.8 60.6 74.5 57.9 70.4 63.8 77.9