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?
54, 55, 59, 61, 61, 62, 68, 70, 72
Since they don't fall on specific scores, I would say the first quartile was 57 and the third quartile was 69.
was? so do i just put 57 and 69? or?
No, your calculations are incorrect. To find the quartiles, first you need to arrange the speeds in ascending order:
54, 55, 59, 61, 61, 62, 68, 70, 72.
Next, you need to find the median, which is the middle value of the dataset. Since we have 9 values, the median will be the 5th value, which is 61.
To find the first quartile (Q1), you need to find the median of the lower half of the dataset. The lower half consists of the values before the median (54, 55, 59). Since we have 3 values, the median of the lower half will be the middle value, which is 55.
To find the third quartile (Q3), you need to find the median of the upper half of the dataset. The upper half consists of the values after the median (62, 68, 70, 72). Again, we have 4 values, so the median of the upper half will be the middle value, which is 68.
So, the correct quartiles for the given dataset are:
Q1 = 55
Median (Q2) = 61
Q3 = 68