Can we trust this interval Here are data on the percent chan

Can we trust this interval? Here are data on the percent change in the total mass (in tons) of wildlife in several West African game preserves in the years 1971 to 1999:⁸

Software gives the 95% confidence interval for the mean annual percent change as–6.66% to –2.55%. There are several reasons why we might not trust this interval.

(a)Examine the distribution of the data. What feature of the distribution throws doubt on the validity of statistical inference?

Solution

we are assume this data is from a normal distribution and we get a 95% CI for mean as

Variable N Mean StDev SE Mean 95% CI
he total mass (in tons) of wildlife 29 -4.872 5.165 0.959 (-6.837, -2.908)

on the basis of sample given we are 95% of the cases sure that the sample mean will fall in  (-6.837, -2.908).

But it may be a not a good sample from population then the proposed CI will not 95% cases contain mean

so on the basis of the data we are 95% confidence\" that the true mean will contain by  (-6.837, -2.908)