This topic contains a solution. Click here to go to the answer

Author Question: Using regression techniques, we can plot a scatter diagram and plot a line to the data using the ... (Read 293 times)

ssal

  • Hero Member
  • *****
  • Posts: 572
Using regression techniques, we can plot a scatter diagram and plot a line to the data using the Least Squares method. Generally, the points do not fall directly on the line. Why does this happen? Is it a problem?
 
  What will be an ideal response?

Question 2

If a total sample of 150 students is taken, determine the number of freshmen and sophomores under the optimum allocation scheme, assuming that the stratum population standard deviations are the same as the corresponding sample values.
 
  A) 89.15
  B) 71.86
  C) 38.48
  D) 60.85



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

dajones82

  • Sr. Member
  • ****
  • Posts: 359
Answer to Question 1

When we estimate by means of simple linear regression, we want to accurately predict one variable with another variable. As noted, however, both explained variation (SSR) and unexplained variation (SSE) will exist. That the points do not fall directly on the line is due to the unexplained variation other factors affecting the model. The Least Squares Method minimizes this unexplained amount of variability. If a large amount of variability is explained, the coefficient of determination will be closer to 1 and the line will give us good estimates and predictors. The only way all the points will fall on a straight line, is if nothing affects the Y variable except the X variable and they have a perfect correlation or +1 or -1. However, the closer the points are clustered about a line, the better the fit of the line and the more the Y variable variation is explained by the X variable.

Answer to Question 2

A




ssal

  • Member
  • Posts: 572
Reply 2 on: Jun 24, 2018
Great answer, keep it coming :)


alexanderhamilton

  • Member
  • Posts: 334
Reply 3 on: Yesterday
Excellent

 

Did you know?

Amoebae are the simplest type of protozoans, and are characterized by a feeding and dividing trophozoite stage that moves by temporary extensions called pseudopodia or false feet.

Did you know?

When blood is deoxygenated and flowing back to the heart through the veins, it is dark reddish-blue in color. Blood in the arteries that is oxygenated and flowing out to the body is bright red. Whereas arterial blood comes out in spurts, venous blood flows.

Did you know?

The cure for trichomoniasis is easy as long as the patient does not drink alcoholic beverages for 24 hours. Just a single dose of medication is needed to rid the body of the disease. However, without proper precautions, an individual may contract the disease repeatedly. In fact, most people develop trichomoniasis again within three months of their last treatment.

Did you know?

The largest baby ever born weighed more than 23 pounds but died just 11 hours after his birth in 1879. The largest surviving baby was born in October 2009 in Sumatra, Indonesia, and weighed an astounding 19.2 pounds at birth.

Did you know?

Malaria mortality rates are falling. Increased malaria prevention and control measures have greatly improved these rates. Since 2000, malaria mortality rates have fallen globally by 60% among all age groups, and by 65% among children under age 5.

For a complete list of videos, visit our video library