The single-sample t-test compares the mean of the sample to a given number (which you supply). The dependent-sample t-test compares the difference in the means from the two variables to a given number (usually 0), while taking into account the fact that the scores are not independent.The independent samples t-test compares the difference in the means from the two groups to a given value (usually 0).he single sample t-test tests the null hypothesis that the population mean is equal to the given number specified using the option H0=. In our example, the t-value for variable write is 4.14 with 199 degrees of freedom.
Vermont had the second-highest median age, at 42.3 years. New Hampshire was third, with a median age of 42. Utah was the youngest state, with a median age of 29.9 years. Officials say among Maine counties, Lincoln is the oldest with a median age of 49.4 years. Androscoggin County was the youngest, at 40.5 years.
From northern Alaska down to the south of Mexico, one lake stands out as the oldest and most geologically unique in all of North America. In Lake County, California, just north of Sonoma and Napa counties, is Clear Lake with a ripe, young age of 480,000âyes, nearly half a million years oldâthe oldest lake on the continent. The average lifespan of a lake is usually about 10,000 years.