Answer:
second to the longest one is right
Step-by-step explanation:
B is the answer .........
A strong positive correlation.
Step-by-step explanation:
The question requires you to calculate the correlation coefficient and then make a conclusion about its value.
Form a table as shown where x is cost of items and y is shipping cost
x y xy x² y²
25 5.99 149.8 625 35.9
45 8.99 404.6 2025 80.8
50 8.99 449.5 2500 80.8
70 10.99 769.3 4900 120.8
190 34.96 1773.2 10050 318.3 ------sum
The formula for correlation coefficient follows;
r=n(∑xy)-(∑x)(∑y) ÷ √{[n∑x²-(x)²] [n∑y²-(y)²]}
where n=4
r=4(1773.2)-(190)(34.96) ÷ √{[4(10050)-190²] [4(318.3)-34.96²]}
r=450÷ √{4100*51)
r=450÷√209100
r=450÷457.3
r=0.98409
The value of r indicates a stronger positive correlation
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Correlation coefficient :brainly.com/question/12528676
Keywords :shipping costs,cost of items, strength of the model
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Answer:
Step-by-step explanation:
The motorist drove at a distance of 90km at a constant speed for the first 40km, and then 20 km/hr faster for the rest of the journey.
The whole journey took him 1hr.
Let S denotes the average speed (in km/hr) for the first 40 km.
Hence we get the following relation,
40/S + (90 - 40)/(S + 20) = 1
or 50/(S + 20) = 1 - 40/S = (S - 40)/S
or (S + 20)(S - 40) = 50S or S^2 - 70S - 800 = 0 or (S - 80)(S + 10) = 0
or S = 80 (km/hr) [Ans]
[S cannot be negative value]
