Question

 

Q1: Define the following terms:

a. correlation coefficient

b. scatter plot

c. bivariate relationship

Q2: Provide an example where the outlier is more important to the research than the other observations?

Q3: Identify when to use Spearman’s rho

 

Answer 1

Q1: Define the following terms:

a. correlation coefficient

b. scatter plot

c. bivariate relationship

a. correlation coefficient:

correlation coeffficient gives the relationship between two variables xand y.

X is called independent variable and

Y is called dependent variable

Denoted with r

Range of r is in between -1<=r<=1

if r=+1 there exists a positive relationship between x and y

if r=+1 there exists a negative relatonship between x and y

if r=0 there is no relationship between x and y

Solution1b:

scatterplot is plot of x and y

From scatterplot we get the relatonship and trend betwen two variables.

We can check whether there is relationship (linear,exponential,polynomial) by scatterplot.

We get form, strength, direction of variables from scatterplot

if the relationship is linear we can go for regression line.

Solution1c:

Bivariate relationship :is the relationship between two variables

For reference on correlation

https://www.simplypsychology.org/correlation.html

Correlation means association - more precisely it is a measure of the extent to which two variables are related. There are three possible results of a correlational study: a positive correlation, a negative correlation, and no correlation.

• A positive correlation is a relationship between two variables in which both variables either increase or decease at the same time. An example would be height and weight. Taller people tend to be heavier.
• A negative correlation is a relationship between two variables in which an increase in one variable is associated with a decrease in the other. An example would be height above sea level and temperature. As you climb the mountain (increase in height) it gets colder (decrease in temperature).
• A zero correlation exists when there is no relationship between two variables. For example their is no relationship between the amount of tea drunk and level of intelligence.

A correlation can be expressed visually. This is done by drawing a scattergram - that is one can plot the figures for one variable against the figures for the other on a graph.

For reference on scatterplot

http://www.amathsdictionaryforkids.com/qr/s/scatter%20plot.html

For bivariate relationship

https://datasagar.com/2018/01/30/uni-variate-distribution-relationships/