Hypothesis testing: using Z test
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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.
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Solution Summary
It provies answers to hypothesis testing related to the life expectancy in US and UK.
Solution Preview
The answers are as follows.
1) The null hypothesis H0: ...
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- BSc , Wuhan Univ. China
- MA, Shandong Univ.
Recent Feedback
- "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
- "excellent work"
- "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
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