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 26 29 31 34 34 35 35 36 37 38
41 41 41 42 43 46 47 48 49 53 55 56 62 67 82

Required:
a. Determine the first and third quartiles.
b. Determine the second decile and the eighth decile.

Answer 1

The answer is below

Explanation:

When computing quartile and decile, the data must be arranged in ascending order.

Given the data points:

13 13 13 20 26 26 29 31 34 34 35 35 36 37 38 41 41 41 42 43 46 47 48 49 53 55 56 62 67 82

The numbers are arranged in ascending order. The total number of terms is 30.

a)

`First \ quartile(Q_1)=(1)/(4)(n+1)^(th)\ term\\\\where\ n=number\ of\ terms. Hence:\\\\Q_1=(1)/(4)(30+1)=7.75^(th)\ term=average\ of\ 7th\ and\ 8th\ term=(29+31)/(2) =30\\\\Q_1=30\\\\Third \ quartile(Q_3)=(3)/(4)(n+1)^(th)\ term\\\\Q_3=(3)/(4)(30+1)=23.25^(th)\ term=average\ of\ 23rd\ and\ 24th\ term=(48+49)/(2) =48.5\\\\Q_3=48.5`

b)

`Second \ decile(D_2)=(2)/(10)(n+1)^(th)\ term\\\\where\ n=number\ of\ terms. Hence:\\\\D_2=(2)/(10)(30+1)=6.2^(th)\ term=average\ of\ 6th\ and\ 7th\ term=(26+29)/(2) =27.5\\\\D_2=27.5\\\\\\Eight \ decile(D_8)=(8)/(10)(n+1)^(th)\ term=(8)/(10)(30+1)=24.8^(th)\ term\\=average\ of\ 24th\ and\ 25th\ term=(49+53)/(2) =51\\\\D_8=51`