Before deciding on what crops to be planted in an estate, the acidity of the soil was measured independently in two parts of the estate. in the first part of the estate, the mean of the 50 observations was pH 6.55 with standard deviation 0.55 ; and the mean of the 45 observations taken in the second part of the estate was pH 5.55 with std deviation 0.45.

find the mean and std deviation for the entire estate.