The highest temperatures measured at Death Valley, California, from 1995 to 2004 are given as a dataset.

127, 125, 125, 129, 123, 126, 127, 128, 128, 125

Find the range and the interquartile range of the dataset.

1 answer

To find the range, we need to subtract the smallest value from the largest value:

Range = 129 - 123 = 6

To find the interquartile range (IQR), we need to first find the first quartile (Q1) and third quartile (Q3) of the dataset.

To do this, we need to put the data in order from smallest to largest:

123, 125, 125, 125, 126, 127, 127, 128, 128, 129

There are 10 data points, so the median is the average of the 5th and 6th values:

Median = (126 + 127) / 2 = 126.5

To find Q1 and Q3, we need to find the medians of the lower half and upper half of the dataset, respectively:

Lower half: 123, 125, 125, 125, 126
Upper half: 127, 127, 128, 128, 129

Q1 = median of lower half = (125 + 125) / 2 = 125
Q3 = median of upper half = (128 + 128) / 2 = 128

Now we can find the IQR by subtracting Q1 from Q3:

IQR = Q3 - Q1 = 128 - 125 = 3

Therefore, the range of the dataset is 6 and the IQR is 3.