Question

1)Adding an outlier in a scatterplot will do which of the following to the correlation coefficient? Explain

a) Increase the correlation coefficient

b) Decrease the correlation coefficient

c) Change the correlation coefficient from positive to negative

d) Change the correlation coefficient from negative to positive

e) All options above are possible

2) When the correlation coefficient is close to +1, it indicates. Please explain

a) changes in one variable cause changes in the other, but we don't know which one causes the other to change

b) Changes in the variable on the x-axis cause changes in the variable on the y-axis

c) Changes in the variable on the y-axis cause changes in the variable on the x-axis

d) Nothing regarding the possible cause and effect relationship between the two variables

T/F: The normal model can be used to describe all distributions. Explain

T/F: An observation with a z-score of 0.5 would be considered an outlier. Explain

T/F: If all of the data in a skewed right data set are converted into z-scores, the distribution of these z-scores will be normally distributed. Explain

When a value of x, that is outside the range of values of x used to construct a regression equation, is used to estimate the value of y given that value of x (using that same regression equation), we call this a_________.

Answer #1

**Please don't hesitate to give a "thumbs up" for the
answer in case the answer has helped you**

Answering first question, as we are allowed to answer 1 question per post. Please post the other questions separately.

1.

**Concept:** In most circumstances an outlier
deviates from the linear regresison line a lot, and therfore
decreases the value of a correlation coefficient and weakens the
regression relationship, but it's also possible that in some
circumstances an outlier may increase a correlation value and
improve regression. If the outlier is exactly on the linear
regression then it increases the correlation coefficient.

Hence, e) All options above are possible is correct

**Answer: e) is correct**

In a scatterplot, which variable( x or y) is the
dependent variable ?
In a scatterplot, which variable
( x or y) is the independent variable ?
Fill in the blank: in a negative correlation, when y
increases, x _______
Fill in the blank: in a positive correlation, when y
increases,
x____________
Why do we study correlation ?
to detect relationships
to make predictions
to show trends
all of these
e. none of these
TRUE-FALSE
IN A SCATTERPLOT, IT IS...

A) Two variables have a high covariance. This means the two
variables have a strong relationship. T/F
B) For a variable x, the sample mean is 8 and the sample
standard deviation is 2. One of the observations is 15. Is this
observation an outlier?
Group of answer choices
Yes, the z-score is greater than 3
No, the z-score is between -3 and 3
Yes, the z-score is between -3 and 3
No, the z-score is less than -3
C)...

For the following scores,
Participant
X
Y
A
1
3
B
3
5
C
2
1
D
2
3
1. Draw a scatterplot by hand. Upload a scanned copy or picture
of the scatterplot.
2. Based on the scatterplot:
a)The correlation between X and Y is zero
b)The correlation between X and Y is 1
c)The correlation between X and Y is positive
d)The correlation between X and Y is negative
3. Compute the Pearson Correlation Coefficient
r =
4....

If the coefficient of correlation is 0.90, the percentage of the
variation in the dependent variable y that is explained by the
variation in the independent variable x is:
A. 81%
B. 0.81%
C. 90%
D. 0.90%
If the coefficient of determination is 0.975, then the slope of
the regression line:
A. could be either positive or negative
B. must be negative
C. must be positive
D. none of the above answers is correct

For the data x= 1,4,5 , and y= 2, 7, 11
a.) Find the correlation coefficient r? What type of
relationship does this represent? Explain. Show all work and
calculations for credit. The formula will be provided on the
board.
b.) Now find our r squared= coefficient of determination. What
does this number tell you in regards to our explanatory variable x
and how it explains our response variable y?
c.) Let’s say if our regression equation is. Y= 2.1154x...

Which of the following values is NOT a valid (or possible)
correlation coefficient? A. 0.7923 B. 0.0001 C. 1.2301 D.
-0.9239
In regression, the space between the regression line (line of
best fit) and the actual data points is the ___________.
A. Standard deviation.
B. Error.
C. Predicted value.
D. Observed value.
In regression, what does error indicate?
A. The difference between the predicted value and the observed
value Y for a given X.
B. The difference between the predicted...

Which of the following statements concerning regression and
correlation analysis is/are true?
A. If the correlation coefficient is zero, then there is no linear
relationship between the two variables.
B. A negative value for the correlation coefficient indicates that
high values of the independent variable are correlated with low
values of the dependent variable.
C. The slope coefficient for a simple linear regression model
measures the expected change in the independent variable for a unit
change in the dependent variable....

Which of the following is NOT a property of the linear
correlation coefficient r?
A. The value of r is always between minus−1 and 1 inclusive.
B.The linear correlation coefficient r is robust. That is, a
single outlier will not affect the value of r.
C.The value of r measures the strength of a linear
relationship.
D.The value of r is not affected by the choice of x or y.

Which of the following statements concerning the linear
correlation coefficient is/are true?
A: If the linear correlation coefficient for two variables is zero,
then there is no relationship between the variables.
B: If the slope of the regression equation is negative, then the
linear correlation coefficient is negative.
C: The value of the linear correlation coefficient always lies
between -1 and 1 inclusive.
D: A correlation coefficient of 0.62 suggests a stronger linear
relationship than a correlation coefficient of -0.82.

For the following scores,
Participant
X
Y
A
1
3
B
3
5
C
2
1
D
2
3
A) Draw a scatterplot by hand. Upload a scanned
copy or picture of the scatterplot.
B)Based on the scatterplot:
The correlation between X and Y is zero
The correlation between X and Y is 1
The correlation between X and Y is positive
The correlation between X and Y is negative
C)Compute the Pearson Correlation
Coefficient
r =
Note: If it...

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