Question

An antique collector takes data on 32 recently auctioned items. For each item the collector records the selling price (Price), the age of the item (Age) and the number of bidders on the item (Bidders). The data appear in the Auction worksheet of the Simple Regression data workbook below.

a) The collector believes that the older an item, the more bidders it will have. To evaluate this belief, draw a scatter plot of the data. Does there appear to be a linear association between the age of an item and the number of bidders?

b) Use JMP to find the sample correlation coefficient between age of an item and the number of bidders. Are the variables significantly correlated at alpha = 0.05?

Auction	Price	Age	Bidders
1	$946	113	9
2	$1,336	126	10
3	$744	115	7
4	$1,979	182	11
5	$1,522	150	9
6	$1,235	127	13
7	$1,483	159	9
8	$1,152	117	13
9	$1,545	175	8
10	$1,262	168	7
11	$845	127	7
12	$1,055	108	14
13	$1,253	132	10
14	$1,297	137	9
15	$1,147	137	8
16	$1,080	115	12
17	$1,550	182	8
18	$1,047	156	6
19	$1,792	179	9
20	$729	108	6
21	$854	143	6
22	$1,593	187	8
23	$1,175	111	15
24	$1,713	137	15
25	$1,356	194	5
26	$1,822	156	12
27	$1,884	162	11
28	$1,024	117	11
29	$2,131	170	14
30	$785	111	7
31	$1,092	153	6
32	$2,041	184	10

Answer 1

A)

there is not positive correlation between age and bidders

B)

SUMMARY OUTPUT
Regression Statistics
Multiple R	0.253749102
R Square	0.064388607
Adjusted R Square	0.03320156
Standard Error	2.792093662
Observations	32
ANOVA
	df	SS	MS	F	Significance F
Regression	1	16.09513951	16.09513951	2.064594566	0.161103153
Residual	30	233.8736105	7.795787016
Total	31	249.96875
	Coefficients	Standard Error	t Stat	P-value	Lower 95%
Intercept	13.3433865	2.69860608	4.944547707	2.72446E-05	7.832097638
Age	-0.026301934	0.018305023	-1.436869711	0.161103153	-0.063685779

r =   -0.253749102

t = -1.4369

p-value = 0.1611

p-value > alpha

hence we we fail to reject the null hypothesis

we conclude that variables are not significantly correlated at alpha = 0.05.