These three tests use very different approaches to test for normality: (1) JB uses the moments-based comparison, (2) SW examines the correlation in the Q-Q plot and (3) AD tests the difference between empirical and theoretical distributions.
Summer solstice: Longest day of the year. June 21 at 6:51 a.m. EDT is the summer solstice, the moment the sun is directly shining down on the Tropic of Cancer, an imaginary line north of the equator. This is the longest day of the year for the Northern Hemisphere and marks the beginning of summer.
Hence the notion of a solstice day is useful. The term is colloquially used like midsummer to refer to the day on which solstice occurs. The summer solstice day has the longest period of daylight â except in the polar regions, where daylight is continuous, from a few days to six months around the summer solstice. 2016 was the first time in nearly 70 years that a full moon and the summer solstice concur on the same day.