Question

The Thomas Supply Company Inc. is a distributor of gas-powered generators. As with any business, the length of time customers take to pay their invoices is important. Listed below, arranged from smallest to largest, is the time, in days, for a sample of The Thomas Supply Company Inc. invoices. 13 13 13 20 26 28 30 33 34 34 35 35 36 37 38 41 41 41 42 46 46 47 48 52 53 55 56 62 67 82 Determine the first and third quartiles. Determine the second decile and the eighth decile. Determine the 67th percentile.

Answer 1

Total number of points = 30

The data is already sorted in ascending order of magnitude.

i) To find the first quartile,

30/4 = 7.5 point in the data = 33

First Quartile = 33

ii) To find the third quartile,

30*3/4 = 22.5 point in the data = 48

Third Quartile = 48

iii) To find the second decile,

30*2/10 = 6^th point in the data = 28

Second decile = 28

iv) To find the eighth decile,

30*8/10 = 24^th point in the data = 52

Eighth decile = 52

v) To find the 67th percentile,

30*67/100=20.1 point in the data = 46

Eighth decile = 46