The number of children per household in the US is strongly skewed to the right with a mean of 3.1 children per household and a standard deviation of 1.2 children per household. A person studying demographics selects an SRS of size n = 40 from the population of all households in the US and calculates the sample mean number of children per household. What is the standard deviation of the sampling distribution of the sample mean? Round to 2 decimal places.