# Hypothesis testing: using Z test

Please help with the 6 short questions in the attached file. For the 6th question is it Yes or No

According to the historical data, the life expectancy in the US is equal to the life expectancy in the UK. A new study has been made to see whether this has changed. Records of 255 individuals from US who died recently are selected at random. The 255 individuals lived an average of 77.6 years with a standard deviation of 4.5 years. Records of 230 individuals from UK who died recently are selected at random and independently. The 230 individuals lived an average of 76.6 years with a standard deviation of 4.9 years. Assume that the population standard deviation of the life expectancy can be estimated by the sample standard deviation, since the samples that are used to compute them are quite large. At the 0.05 level of significance, is there enough evidence to support the claim that the life expectancy u1 in US is not equal to the expectancy, u2, in UK.

perform a two tailed test, then fill in the table.

https://brainmass.com/statistics/hypothesis-testing/hypothesis-testing-using-z-test-117341

#### Solution Preview

The answers are as follows.

1) The null hypothesis H0: ...

#### Solution Summary

It provies answers to hypothesis testing related to the life expectancy in US and UK.