A sample of size 168, taken from a normally distributed population whose standard deviation is known to be 8.60, has a sample mean of 80.60. Suppose that we have adopted the null hypothesis that the actual population mean is equal to 80, that is, H0 is that μ = 80 and we want to test the alternative hypothesis, H1, that μ ≠ 80, with level of significance α = 0.1. The upper limit of a 95% confidence interval for the population mean would equal: