The points (15, 10), (25, 20), (30, 22), (40, 32), (55, 53), (60, 55) represent the time, x, it takes 6 people to travel y miles
. The scatterplot below represents the situation.
Based on the information above, how many miles should a person who drives for 48 minutes expect to travel?
32 miles
42 miles
48 miles
54 miles
Based on the information above, how many miles should a person who drives for 48 minutes expect to travel?
32 miles
42 miles
48 miles
54 miles
2 answers:
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Answer:
(a) See below
(b) r = 0.9879
(c) y = -12.629 + 0.0654x
(d) See below
(e) No.
Step-by-step explanation:
(a) Plot the data
I used Excel to plot your data and got the graph in Fig 1 below.
(b) Correlation coefficient
One formula for the correlation coefficient is
The calculation is not difficult, but it is tedious.
(i) Calculate the intermediate numbers
We can display them in a table.
<u> x </u> <u> y </u> <u> xy </u> <u> x² </u> <u> y² </u>
36 0.22 7.92 1296 0.05
67 0.62 42.21 4489 0.40
93 1.00 93.00 20164 3.46
433 11.8 5699.4 233289 139.24
887 29.3 25989.1 786769 858.49
1785 82.0 146370 3186225 6724
2797 163.0 455911 7823209 26569
<u>3675 </u> <u> 248.0 </u> <u> 911400 </u> <u>13505625</u> <u> 61504 </u>
9965 537.81 1545776.75 25569715 95799.63
(ii) Calculate the correlation coefficient
(c) Regression line
The equation for the regression line is
y = a + bx where
(d) Residuals
Insert the values of x into the regression equation to get the estimated values of y.
Then take the difference between the actual and estimated values to get the residuals.
<u> x </u> <u> y </u> <u>Estimated</u> <u>Residual </u>
36 0.22 -10 10
67 0.62 -8 9
93 1.00 -7 8
142 1.86 -3 5
433 11.8 19 - 7
887 29.3 45 -16
1785 82.0 104 -22
2797 163.0 170 - 7
3675 248.0 228 20
(e) Suitability of regression line
A linear model would have the residuals scattered randomly above and below a horizontal line.
Instead, they appear to lie along a parabola (Fig. 2).
This suggests that linear regression is not a good model for the data.
If you have information about 5 servings, assuming that all servings have the same calories, the information about one serving is simply obtained by dividing the total by 5.
So, each serving has
calories