Question

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. The correlation between X and Y is:

a)large and positive. As X increases, Y increases

b)large and positive. As X increases, Y decreases

c)medium and positive. As X increases, Y increases

d)medium and positive. As X increases, Y decreases

e)large and negative. As X increases, Y increases

f)large and negative. As X increases, Y decreases

Answer 1

(1) copy and paste the data into excel

select data, click on insert tab, select scatter plot

This is hand made scatter plot.

(2) We can see that data points are moving, i.e. slope is upward

so, we can say that the correlation must be positive

option c)The correlation between X and Y is positive

(3) Use excel function CORREL

select x and y data as array1 and array2

we get

Correlation coefficient r= CORREL(x data, y data) = 0.5

(4) r = 0.5 is a positive and moderate correlation

therefore, option c)medium and positive. As X increases, Y increases