http://www.ck12.org Chapter 7. Organizing and Displaying Data
Determine the values forQ 1 andQ 3.
5 , 18 , 19 , 20 , 21 , 22 , 23 , 24
Q 1 =
18 + 19
2
=
37
2
= 18. 5 Q 3 =
22 + 23
2
=
45
2
= 22. 5
Calculate the difference betweenQ 1 andQ 3 :Q 3 −Q 1 = 22. 5 − 18. 5 = 4 .0.
Multiply this difference by 1.5:( 4. 0 )( 1. 5 ) = 6 .0.
Finally, compute the range.
Q 1 − 6. 0 = 18. 5 − 6. 0 = 12. 5
Q 3 + 6. 0 = 22. 5 + 6. 0 = 28. 5
.
Are there any data values below 12.5? Yes, the value of 5 is below 12.5 and is, therefore, an outlier.
Are there any values above 28.5? No, there are no values above 28.5.
b. Organize the given data set as follows:
13 , 15 , 19 , 14 , 26 , 17 , 12 , 42 , 18
12 , 13 , 14 , 15 , 17 , 18 , 19 , 26 , 42
Determine the values forQ 1 andQ 3.
12 , 13 , 14 , 15 , 17 , 18 , 19 , 26 , 42
Q 1 =
13 + 14
2
=
27
2
= 13. 5 Q 3 =
19 + 26
2
=
45
2
= 22. 5
Calculate the difference betweenQ 1 andQ 3 :Q 3 −Q 1 = 22. 5 − 13. 5 = 9 .0.
Multiply this difference by 1.5:( 9. 0 )( 1. 5 ) = 13 .5.
Finally, compute the range.