Find the correlation coefficient &amp; interpret it. Find &amp; interpret the slope.

1 / 14

# Find the correlation coefficient & interpret it. Find & interpret the slope. - PowerPoint PPT Presentation

A medical researcher wishes to determine how the dosage (in mg) of a drug affects the heart rate of the patient. Find the correlation coefficient &amp; interpret it. Find &amp; interpret the slope. Find &amp; interpret the y-intercept. Give the least squares regression line.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' Find the correlation coefficient & interpret it. Find & interpret the slope.' - wilda

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
A medical researcher wishes to determine how the dosage (in mg) of a drug affects the heart rate of the patient.
• Find the correlation coefficient & interpret it.
• Find & interpret the slope.
• Find & interpret the y-intercept.
• Give the least squares regression line.
A medical researcher wishes to determine how the dosage (in mg) of a drug affects the heart rate of the patient.
• Find the correlation coefficient & interpret it.
• Find & interpret the slope.
• For every additional mg the heart rate decreases by 38.56 bpm.
• Find & interpret the y-intercept.
• Write LSRL:

### Residuals

Section 3.2B

Residuals
• Variation in the y values can be effectively explained when the residuals are small – close to the line.
• Remember a residual = observed – exp.
The equation to explain the relationship between drug dosage and heart rate is shown below.

Find the predicted value for a dosage of 0.4 mg.

Find the residual for (0.4, 80).

The equation to explain the relationship between drug dosage and heart rate is shown below.Find the residuals for each value.

* The sum of the residuals is always zero!

Residual Plot
• It is a scatterplot of the residuals vs the explanatory variable.
• They help us to assess how well a regression line fits the data.
• The residual plot should show no obvious pattern
• The residuals should be relatively small.

The equation to explain the relationship between drug dosage and heart rate is shown below.Graph the residual Plot. Is the linear model appropriate?

* The sum of the residuals is always zero!

Height vs Shoe size – residual plot

Good residual plot – show relatively no pattern.

Standard Deviation of the Residuals
• It represents the approximate size of a “typical” or “average prediction error (residual).
• Formula:
The equation to explain the relationship between drug dosage and heart rate is shown below.Find the standard deviation of the residuals.
Homework

*Page 191 (43, 45, 55, 60, 62)