Question

As the new manager of a small convenience​ store, you want to understand the shopping patterns of your customers. You randomly sample 20 purchases from​ yesterday's records. The amounts of those purchases​ (in dollars) are shown to the right. Complete parts​ a) through​ d).

38.82 37.15 57.52 21.33 76.94 2.75 33.93 82.1 42.95 72.53 32.98 64.15 48.81 38.76 47.16 46.05 50.38 10.3 31.19 65.48

a) Find the quartiles using technology. Q1 Q3

​b) Find the quartiles using the Tukey method. Q1. Q3 ​

c) Find the IQR using the quartiles from part b. IQR

d) Find the standard deviation.

Answer 1

a) Find the quartiles using technology. Q1 Q3

Formula Ref:

b)[Tukey's hinge method]

Minimum=2.75,

Q1=33.455,

Median=44.5,

Q3=60.835,

Maximum=82.1

c) Find the IQR using the quartiles from part b. IQR

IQR = q3-q1 = 60.835-33.455 = 27.38

d) Find the standard deviation.

using excel formula STDEV(A2:A21)

Standard deviation = 20.90