At one hospital in 1992, 674 women were diagnosed with breast ...

[fox]

At one hospital in 1992, 674 women were diagnosed with breast cancer. Five years later, 88 of the Caucasian women and 63 of the African American women were still alive.
 
  This observational study shows an association between race and breast cancer survival--that Caucasian women are more likely to survive breast cancer than African American women. How could this study be modified to make it a designed experiment? Comment on the feasibility of the designed experiment that you described.

Question 2

Which of the following statements concerning the linear correlation coefficient 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 line is negative, then the linear correlation coefficient is negative.
 
  C: The value of the linear correlation coefficient always lies between -1 and 1.
 
  D: A linear correlation coefficient of 0.62 suggests a stronger linear relationship than a linear correlation coefficient of -0.82.
  A) B and C B) C and D C) A and D D) A and B

[kxciann]

Answer to Question 1

To make the study a designed experiment, a researcher could start with a randomly chosen group of women who had been diagnosed with breast cancer in 1992. The women would then be divided into two groups: Caucasian women and African American women. The two groups of women would be required to receive the exact same cancer treatment over the next five years; then the survival rates would be recorded. This designed experiment may be infeasible because some of the women may not wish to receive the treatment provided versus a treatment that could be more appropriate to their case (radiation, chemotherapy, surgery) or any cancer treatment whatsoever. Controlling the treatment method may not be sufficient to establish whether there is a causation between race and survival rate. Other factors may affect the survival statistics, such as economic status, age, other health factors, etc.

Answer to Question 2

A

[fox]

Both answers were spot on, thank you once again

[kxciann]

Great! Please up vote