Question

The dataset Bravman.xlsx reports some variables of a sample of transactions for a company.

Is there evidence at the 1% significance level, that the percentage of those with bad credit (below a score 650) is more than 20% of the population?  Use the 5-step: State the null and alternative hypothesis, state the level of  significance. identify a test statistics,  determine  the rejection region and state your conclusion . . Interpret the results in context.

Data:

Customer Number	Wait Time (min)	Purchase Amount ($)	Customer Age	Credit Score
1	1.3	455	28	746
2	4.5	490	32	760
3	0.8	495	45	744
4	4.2	742	58	749
5	8.2	603	38	696
6	1.4	420	41	673
7	1.8	350	48	625
8	2.3	189	34	747
9	9.5	281	28	743
10	8.4	360	31	638
11	3.2	393	28	622
12	1.4	888	62	837
13	6.4	950	54	884
14	7.8	646	38	690
15	6.5	527	43	718
16	9.8	354	48	645
17	3.4	431	28	529
18	4.8	528	35	590
19	5	981	50	837
20	1.8	847	41	831
21	6.1	716	39	600
22	3.4	330	42	683
23	7.8	549	36	723
24	2.8	551	34	692
25	1.2	468	37	775

Answer 1

Arranged data set as per Credit Score:

Customer Number	Wait Time (min)	Purchase Amount ($)	Customer Age	Credit Score
17	3.4	431	28	529
18	4.8	528	35	590
21	6.1	716	39	600
11	3.2	393	28	622
7	1.8	350	48	625
10	8.4	360	31	638
16	9.8	354	48	645
6	1.4	420	41	673
22	3.4	330	42	683
14	7.8	646	38	690
24	2.8	551	34	692
5	8.2	603	38	696
15	6.5	527	43	718
23	7.8	549	36	723
9	9.5	281	28	743
3	0.8	495	45	744
1	1.3	455	28	746
8	2.3	189	34	747
4	4.2	742	58	749
2	4.5	490	32	760
25	1.2	468	37	775
20	1.8	847	41	831
12	1.4	888	62	837
19	5	981	50	837
13	6.4	950	54	884