Question

from a sample of 10 observations , the following results were obtained: summation Yi =1110, summation Xi =1700, summation XiYi =205500 , summation Xi^2 =322000, summation Yi^2 =132100 . with coefficient of correlation r= 0.9758. But on rechecking these calculations ,it was found that two pairs of observations were recorded : Y = 90,140. and X =120, 220. INSTEAD of Y =80, 150. AND X =110, 220. What will be the effect of this error on r? obtain the correct r .

Answer #1

Following is a simple linear regression model:
The following results were obtained from some statistical
software.
R2 = 0.523
syx (regression standard error) = 3.028
n (total observations) = 41
Significance level = 0.05 = 5%
Variable Parameter Estimate Std. Error of
Parameter Est.
Intercept 0.519 0.132
Slope of X -0.707 0.239
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What is the meaning of R2? Show your work.

An analyst has an independent and identically distributed sample
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regresses Y on X, to obtain the OLS slope coefficient
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i. Suppose the analyst discovers that the 1st observation
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particular, the recorded value Y1 was much higher than it should
have been. The analyst knows that X1 − X = 0. Should the analyst be...

A random sample of nine custom homes currently listed for sale
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denotes size, in hundreds of square feet, rounded to the nearest
hundred, and y denotes price, in thousands of dollars, rounded to
the nearest thousand.
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n=9, ∑xi=270, ∑x2i=8316, ∑yi=5552, ∑y2i=3504412,
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X
6
3
5
8 12
Y
4
8
6
10 14
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Find the Linear Regression equation.
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Please show calculations. Thank you.

Ten salespeople were surveyed and the average number of client
contacts per month, x, and the sales volume, y (in thousands), were
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44 40 41 46
50 48 50 55 Y
50 55 42 45
30 80 90 95
110 130
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c) Construct the scatter plot and graph the
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The following sample observations were randomly selected.
x
5
3
6
3
4
4
6
8
y
13
15
7
12
13
11
9
5
Click here for the Excel Data File
Determine the coefficient of correlation and the coefficient of
determination. Interpret the association between x and
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Negative amounts should be indicated by a minus sign.)
x
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x−x¯x-x¯
y−y¯y-y¯
(x−x¯)2x-x¯2...

The following sample data were obtained from different
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138
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135
140
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100
100
80
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Question 1:
The following information is obtained from a sample data
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Find the estimated regression line.
y ^ = Enter you answer to the field 1 in accordance
to the question statement + ( Enter you answer to the field 2 in
accordance to the question statement ) x
Question 2:
A sample data set produced the following...

The following table show the systolic blood pressure and the
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Show formulas used and how each determination/sum is
calculated.
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Diastolic (Y) 70, 110, 80, 98, 70, 75
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b) At alpha equal to 0.05, determine whether a correlation
exists (test R)
c) Determine the regression equation and determine the standard
error.
d) Estimate the diastolic blood pressure for an...

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