1. The skid properties of a current snow tire have been tested, and a mean skid distance of 40 m has been established for standardized conditions. A new, more expensive tire is developed, but tests on a sample of 18 random new tires yield a mean skid distance of 41 m with a standard deviation of 3.8 m. Assume that the skid distance is normally distributed. Test the claim that mean skid of the new tire is more than of the current type at the significance level 10%.