Question

Consider the relationship between the number of bids an item on eBay received and the item's selling price. The following is a sample of 5

items sold through an auction.

Price in Dollars	23

26

32

44

50

Number of Bids	10

13

14

15

17

Step 3 of 3 :

Calculate the correlation coefficient, r. Round your answer to three decimal places.

Answer 1

Count	x	y	xy	x2	y2
1	23	10	230	529	100
2	26	13	338	676	169
3	32	14	448	1024	196
4	44	15	660	1936	225
5	50	17	850	2500	289
Total	175	69	2526	6665	979

From the above data:

Sum (x) = 175,Sum (y) = 69, Sum (xy) = 2526,

Sum (x)² = 6665, (Sum x)² = (175)² = 30625,

Sum (y)² = 979, (Sum y)² = (69)² = 4761,

Sum (x) * Sum (y) = 175 * 69 = 12075,

n = 5

Substituting these values in the equation for r, we get

Therefore r = 0.92269    0.923 (Rounding to 3 decimal places)

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