According to the historical data, the life expectancy in Germany is less than or equal to the life expectancy in the United States. A new study has been made to see whether this has changed. Records of 225 individuals from Germany who died recently are selected at random. The 225 individuals lived an average of 78.1 years with a standard deviation of 6.8 years. Records of 230 individuals from the United States who died recently are selected at random and independently. The 230 individuals lived an average of 76.4 years with a standard deviation of 7.4 years. Assume that the population standard deviations of the life expectancy can be estimated by the sample standard deviations, since the samples that are used to compute them are quite large. At the 0.01 level of significance, is there enough evidence to support the claim that the life expectancy, u1, in Germany is greater than the life expectancy,u2 , in the United States? Perform a one-tailed test.
Answer the following:
- null hypothesis:
- alternative hypothesis:
- type of test statistic:
- value of the test statistic rounded to at least 3 decimal places:
- p value rounded to at least 3 decimal places:
- can we support the claim that the life expectancy in Germany is greater than the life expectancy in the US?