In a study of environmental lead exposure and IQ, the data was collected from 148 children in Boston, Massachusetts. Their IQ score an age 10 approximately follow a normal distribution with a mean of 115.9 and standard deviation of 14.2. Suppose one child had an IQ of 74.
A) Calculate the lower fence for the IQ data, which is the lower limit value that the IQ score can be without being considered an outlier.
B) Then, calculate the probability of obtaining an IQ score value of 74 or less.