a. To calculate the mean (average) for the given data, you need to sum up all the values and divide by the total number of values. In this case, you would add up all the given GDP values: 173 + 49 + 254 + 103 + 1901 + 258 + 237 + 62 + 748 + 403 + 67 + 55 + 652 + 276 + 143 + 127 + 163 + 219 + 52 + 295 + 379 + 384 + 270 + 97 + 244 + 36 + 90 + 126 + 60 + 487 + 80 + 1160 + 425 + 35 + 478 + 148 + 174 + 570 + 49 + 164 + 40 + 255 + 1207 + 115 + 26 + 424 + 340 + 65 + 248 + 39 = 12444.
Next, divide the sum by the total number of values, which is 50 in this case: 12444 / 50 = 248.88.
So, the mean for these data is approximately 248.88 billion dollars.
The median is the middle value when the data is arranged in ascending or descending order. To find the median, you first need to sort the data from smallest to largest: 26, 35, 36, 39, 40, 49, 49, 52, 55, 60, 62, 65, 67, 80, 90, 97, 103, 115, 1160, 1207, 127, 143, 148, 163, 164, 173, 174, 1901, 219, 237, 244, 248, 254, 255, 258, 270, 276, 295, 340, 379, 384, 403, 424, 425, 478, 487, 570, 652, 748, 115.
Since the number of values is even (50), there is no exact middle value. Instead, you need to find the average of the two middle values, which in this case are the 25th and 26th values. So, the median would be (173 + 174) / 2 = 173.5 billion dollars.
Regarding whether these values are sample statistics or population parameters, we don't have enough information in the question to definitively determine this. In general, when calculating measures from an entire population's data, the results are referred to as population parameters. However, if the data represents a sample from a larger population, the calculated measures would be sample statistics.
b. To determine if the data have a mode, you need to look for the value that appears most frequently in the dataset. From the given data, you can observe that the value 49 appears twice, making it the most frequently occurring value. Therefore, the dataset does have a mode, and the mode is 49 billion dollars.