In a study using data from the Danish Twin Registry, it is claimed that twins (specifically male twins) live longer than singletons. You decide to run a test to see if this is true in the United States. You randomly sample the death records in New York City of 70 males who were born with a twin and 100 males who were born as a single birth. (a) If the mean life expectancy for all 170 males was 78.3 years with a population standard deviation of a = 4.3 years, calculate a 95% confidence interval for the mean life expectancy (in years) of all males. (Use a table or technology. Round your answers to two decimal places.) 78.03 X + z critical value.. Xz critical value.. HO: HT-MS=0 H: HT-Hs < 0 (b) What would be the appropriate null and alternative hypotheses? OHO: HT-MS-0 H: HT-HS > 0 Ho: HT-H = 0 H: HT-US *0 Ho: My-Hs> 0 H: HTHS 0 O 79.37 yr O x (c) If after conducting the test you found a t score of 1.47 and a P-value of 0.073, what would be the appropriate conclusion if you were using a significance level of 0.05? Because 0.073 > a, we reject the null hypothesis. Because the 0.073 a, we fail to reject the null hypothesis. Because the 0.073