Still the same variable hwy and testing whether the median significantly differs from 25. The code is pretty simple.
Sign test first (you need to install BSDA package to run the sign test):
> library(BSDA) > SIGN.test(mpg$hwy, md = 25)
One-sample Sign-Test data: mpg$hwy s = 101, p-value = 0.2796 alternative hypothesis: true median is not equal to 25 95 percent confidence interval: 23 25 sample estimates: median of x 24 Conf.Level L.E.pt U.E.pt Lower Achieved CI 0.9422 23 25 Interpolated CI 0.9500 23 25 Upper Achieved CI 0.9575 23 25
Then Wilcoxon signed rank test:
> wilcox.test(mpg$hwy, mu=25)
Wilcoxon singed rank test with continuity correction data: mpg$hwy V = 8223.5, p-value = 4.535e-05 alternative hypothesis: true location is not equal to 25