As cars passed a checkpoint, the following speeds were clocked and recorded.
Speed (mph): 55 62 61 54 68 72 59 61 70
so the range is 54 to 72
the min is 54
the max is 72
1quartile is 55?
2nd is 61
3rd is 70?
is it wrong?
Based on the data you provided, let's calculate the quartiles:
Step 1: Arrange the speeds in ascending order:
54, 55, 59, 61, 61, 62, 68, 70, 72.
Step 2: Find the median (2nd quartile):
Since there are nine data points, the median will be the middle value. In this case, the middle value is the 5th number, which is 61.
Step 3: Find the first quartile (Q1):
To find the first quartile, we need to locate the median of the lower half of the data set. In this case, the lower half of the data set is {54, 55, 59, 61}. Since there are four numbers, the median will be the average of the 2nd and 3rd numbers when they are sorted in ascending order. So, (55 + 59) / 2 = 57.
Step 4: Find the third quartile (Q3):
To find the third quartile, we need to locate the median of the upper half of the data set. In this case, the upper half of the data set is {61, 62, 68, 70, 72}. Since there are five numbers, the median will be the average of the 3rd and 4th numbers when they are sorted in ascending order. So, (68 + 70) / 2 = 69.
So, the correct quartiles for the given data set are:
Q1 = 57
2nd quartile (median) = 61
Q3 = 69
Therefore, your previous answer was incorrect. The corrected values for the quartiles are 57 for Q1, 61 for the 2nd quartile (median), and 69 for Q3.