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Be certain to have the data in order from least to greatest when finding measures of spread. You will need this for the median, range, and interquartile range.
Mean: 10.375
Median: 10
Range: 11
Interquartile Range: 5
We are given a set of numbers and we will find its mean, median, range, and interquartile range. {4,8,9,9,11,12,15,15} The numbers are already ordered from least to greatest, so we are ready to get started!
Substitute values
Add terms
Calculate quotient
To determine the median, we find the middle value, or the mean of the two middle values, of the ordered data. {4,8,9, 9, 11,12,15,15} In this list, there is an even number of values, so we need to find the average of the two middle values. Median=9+11/2=20/2=10
The range is the difference between the least and the greatest data values. { 4,8,9,9,11,12,15, 15} The least data value is 4 and the greatest data value is 15. range= 15- 4=11
The IQR is the difference between the first quartile and the third quartile. The first quartile is the median of the lower half and the third quartile is the median of the upper half of the data set. {4,8,9,9,11,12,15,15} We will begin with calculating the first quartile, Q_1, and the third quartile, Q_3. Remember that when there is an even number of values the median is the average of the two middle values. Q_1=8+9/2= 8.5 [0.8em] Q_3=12+15/2= 13.5 Now, let's calculate the IQR! IQR= 13.5- 8.5=5