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

(a) Determine the first and third quartiles.

Q1 = ?
25%*30 = 7.5
Locator = 8
Q1 is the 8th element = 33.25
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Q3 = ?
75%*30 = 22.5
Locator = 23
Q3 is the 23rd data element = 50.25

(b) Determine the second decile and the eighth decile.

D2 = ?
20%*30 = 6
Locator = 6
D2 is the 6th data element = 27.8
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D8 = ?
80%*30 = 24
Locator = 24
D8 is the 24th data element = 52.6
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(c) Determine the 67th percentile = ?
67%*30 = 20.1
locator = 21
67%ile is the 21st data element = 47