Respuesta :
There's a strong correlation between Shelly's age and savings.
There's a positive correlation between Shelly's age and savings.
Let,
Shelly's age be denoted by x
Money saved by Shelly be denoted by y
Now,
x y
10 $20
20 $5000
The sample means are represented with the symbols x(bar) and y(bar), Hence means for Shelly's age (x(bar)) and Money saved (y(bar)) are easily calculated as follows:
x(bar) = (10+20)/2
= 30/2
= 15
y(bar) = (20+5000)/2
= 5020/2
= 2510
Now,
x (xi - x(bar)) y (yi-y(bar))
10 10-15 = -5 20 20-2510 = -2490
20 20-15 = 5 5000 5000-2510 = 2490
∑[(xi - x(bar)) (yi-y(bar))] = (-5)(-2490) + (5)(2490)
= 12450 + 12450
= 24900
Now,
∑[(xi - x(bar))^2]
= (-5)^2 + 5^2
= 25 + 25
= 50
∑[(yi - y(bar))^2]
= (-2490)^2 + 2490^2
= 12400200
Hence,
√[∑[(xi - x(bar))^2] * ∑[(yi - y(bar))^2]]
= √(50 * 12400200)
= √31620510
= 17782.15
Therefore,
r = ∑[(xi - x(bar)) (yi-y(bar))] / √[∑[(xi - x(bar))^2] * ∑[(yi - y(bar))^2]]
r = 24900/17782.15
r = 1.4
But, according to given correlation coefficient (r) = 0.85
The closer r is to zero, the weaker the linear relationship.
Positive r values indicate a positive correlation, where the values of both variables tend to increase together.
Negative r values indicate a negative correlation, where the values of one variable tend to increase when the values of the other variable decrease.
Therefore, There's a strong positive correlation between Shelly's age and savings.
Learn more about correlation coefficient at : https://brainly.com/question/27226153?referrer=searchResults
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