**Quartiles****Lower**

**Quartile - LQ or L1**

Upper Quartile - UQ or Q3

Median - Q2

Interquartile Range - IQR

To find the lower quartile, you find the median of the lower set of numbers.

To find the upper quartile you find the median of the upper set of numbers.

The median is the middle number.

The interquartile range is the range (difference) between the lower and upper quartiles.

Upper Quartile - UQ or Q3

Median - Q2

Interquartile Range - IQR

To find the lower quartile, you find the median of the lower set of numbers.

To find the upper quartile you find the median of the upper set of numbers.

The median is the middle number.

The interquartile range is the range (difference) between the lower and upper quartiles.

10,7,7,6,12,9,8,10,7,9,10,6,9,7,10

Find the lower quartile, upper quartile, median and interquartile range for this data:

First of all you have to put the data in order -

6,6,7,7,7,7,8,9,9,9,10,10,10,10,12

Median - 9 becuase when you cancel down the numbers the number left in the middle is 9. Or if you count how many numbers there are which is 15. You then halve 15 which is 7.5, after that you round it up to a whole number which is 8. The eighth number in the data when it is in order is ...9. That is why 9 is the median.

Lower Quartile - 7 because when you find the median of the lower set of numbers it is 7. There are 7 numbers in the lower set, halve of 7 is 3.5. Rounding that up is 4. The fourth number in the lower set of data when it is in order is ...7. If you cancel it down it is still 7.

__Question 1:__

The data from how many 14 - 15 year olds sleep in 1986 -10,7,7,6,12,9,8,10,7,9,10,6,9,7,10

Find the lower quartile, upper quartile, median and interquartile range for this data:

First of all you have to put the data in order -

6,6,7,7,7,7,8,9,9,9,10,10,10,10,12

Median - 9 becuase when you cancel down the numbers the number left in the middle is 9. Or if you count how many numbers there are which is 15. You then halve 15 which is 7.5, after that you round it up to a whole number which is 8. The eighth number in the data when it is in order is ...9. That is why 9 is the median.

Lower Quartile - 7 because when you find the median of the lower set of numbers it is 7. There are 7 numbers in the lower set, halve of 7 is 3.5. Rounding that up is 4. The fourth number in the lower set of data when it is in order is ...7. If you cancel it down it is still 7.

**Upper Quartile - 10 because the median of the upper set of numbers is 10. There are 7 numbers in the upper set, halve of 7 is 3.5. Rounding that up is 4. The fourth numbers in the upper set of data it is in order is ...10. If you cancel it down it is still 10.**

Interquartile range - 3 because the range (difference) between the lower and upper quartile is 10 - 7. The answer is 3. Therefore the interqaurtile range is

Interquartile range - 3 because the range (difference) between the lower and upper quartile is 10 - 7. The answer is 3. Therefore the interqaurtile range is

**3.**

1. 72, 63, 82, 72, 25, 84, 76, 72, 91, 67, 77, 80, 89, 70, 82

2. 22, 2, 5, 7, 9, 0, 13, 5, 10, 2, 5 , 9, 4, 1, 18

3. 1, 6, 3, 0, 7, 1, 10, 1, 3, 0, 2, 6, 4, 1, 18

__Questions__

Find the interquartile range, upper quartile, lower quartile and median for the questions below.1. 72, 63, 82, 72, 25, 84, 76, 72, 91, 67, 77, 80, 89, 70, 82

2. 22, 2, 5, 7, 9, 0, 13, 5, 10, 2, 5 , 9, 4, 1, 18

3. 1, 6, 3, 0, 7, 1, 10, 1, 3, 0, 2, 6, 4, 1, 18

__Box Plots__

**In box plots there are minimum values, maximum values, lower quartiles, upper**

quartiles, median and horizontal lines.

quartiles, median and horizontal lines.

**The minimum value goes first (the smallest number).**

The maximum value goes last (the largest number).

The lower quartile goes next to the minimum value.

The upper quartile goes in front of the maximum value.

The median goes in the middle.

The horizontal lines join up the minimum value to the

lower quartile and the upper quartile to the maximum value.

They also go on the top of the lower quartile, upper quartile and the median.

The maximum value goes last (the largest number).

The lower quartile goes next to the minimum value.

The upper quartile goes in front of the maximum value.

The median goes in the middle.

The horizontal lines join up the minimum value to the

lower quartile and the upper quartile to the maximum value.

They also go on the top of the lower quartile, upper quartile and the median.