In a statistics class, the standard deviation of the heights of all students was 3.93.9 inches. the standard deviation of the heights of males was 3.43.4 inches and the standard deviation of females was 3.33.3 inches. why is the standard deviation of the entire class more than the standard deviation of the males and females considered separately?

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 3 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30∘c on monday, but decreased at a constant rate in the next 3 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.