Final answer:
The point estimate for the difference between the population means of non-smokers and smokers, based on the provided sample data, is 8 years. This is calculated by subtracting the sample mean life expectancy of smokers from that of non-smokers.
Step-by-step explanation:
The point estimate for the difference between the means of two populations can be calculated as the difference between the two sample means. In this scenario, we have a sample of non-smokers with a mean life expectancy of 76 years and a sample of smokers with a mean life expectancy of 68 years.
To calculate the point estimate for the difference of the population means, we simply subtract the mean of the smokers' sample from the mean of the non-smokers' sample:
Point estimate
= Mean of non-smokers - Mean of smokers
Point estimate
= 76 years - 68 years
Point estimate
=
8 years
This point estimate suggests that, based on the samples, non-smokers may live 8 years longer on average than smokers. However, this is just an estimate based on the samples provided, not a definitive measure of the true population means.