Final answer:
The median of the dataset 1; 1; 2; 3; 4; 4; 5; 5; 6; 7; 7; 8; 9 is 5, which is the middle value. None of the provided answer choices match this value.
Step-by-step explanation:
The median of a dataset is the middle value when the data are arranged in ascending order. Given the dataset 1; 1; 2; 3; 4; 4; 5; 5; 6; 7; 7; 8; 9, there are 13 values in total, which is an odd number. To find the median, one must locate the middle value. Since there are 6 values on either side of the middle value, the median will be the 7th value in the ordered list. Counting in sequence, the median here is 5. There seems to be an error in the question, as none of the choices (a) 30, (b) 29, (c) 42, or (d) 38 match the calculated median. Therefore, based on the given dataset, none of the provided options are correct, and the actual median should be 5.