If there is no expression, it surely is equal to 0.
Answer:

B. The coefficient of determination is 0.1980, 19.8% of the variation is explained by the linear correlation, and 80.2% is explained by other factors.
Step-by-step explanation:
Previous concepts
The correlation coefficient is a "statistical measure that calculates the strength of the relationship between the relative movements of two variables". It's denoted by r and its always between -1 and 1.
Solution to the problem
In order to calculate the correlation coefficient we can use this formula:
On this case we got that r =0.445
The determinaton coefficient is just:

And we can put it on % and we got 19.8%. And represent the variation explained by a linear model. The best option on this case would be:
B. The coefficient of determination is 0.1980, 19.8% of the variation is explained by the linear correlation, and 80.2% is explained by other factors.
Since the explained variation is 19.8% and the remain 100-19.8= 80.2% is explained by other factors.
Answer:
24
Step-by-step explanation:
30 secs = 0.5 min
thus 84 / 3.5 min = 168 / 7 = 24
a. Answer: m = 2
<u>Step-by-step explanation:</u>
f(x) = x² - 4x + 1
f(m) = m² - 4m + 1 = -3
m² - 4m + 4 = 0
(m - 2)(m - 2) = 0
m = 2
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b. Answer: k = 2 and k = 5
<u>Step-by-step explanation:</u>
f(x) = x² - 7x + 14
f(k) = k² - 7k + 14 = 4
k² - 7k + 10 = 0
(k - 2)(k - 5) = 0
k = 2 k = 5