a. After first assuming the data below represents a population instead of a sample, what is the z-score of the last piece of data listed (the data value 55)?

b. Interpret the meaning of this z-score in the context of the data set.

9	13	44	2	77
35	38	8	41	16
15	27	47	51	20
48	59	17	34	55
21	0	37	11	68
7	45	23	63	32
23	25	12	62	4
19	9	38	0	55

Purchases	Frequency	Relative Frequency
0 to 15	12	0.30000
16 to 31	9	0.22500
32 to 47	10	0.25000
48 to 63	7	0.17500
64 to 79	2	0.05000