Question: How well materials conduct heat matters when designing houses, for example. Conductivity is measured in terms of watts of heat power transmitted per square meter of surface per degree Celsius of temperature difference on the two sides of the material. In these units, glass has conductivity about 1. The national Institute of Standards and Technology provides exact data on property of materials. Here are 11 measurements of the heat conductivity of a particular type of glass.

1.11 1.07 1.11 1.07 1.12 1.08 1.08 1.18 1.18 1.18 1.12

(a) We consider this an SRS of all specimens of glass of this type. Make a stemplot. Is there any sign of major deviation from normality?

(b) Give a 95% confidence interval for the mean conductivity.