stats question

Question

Do left-handed people live shorter lives than right-handed people? A study of this question examined a sample of 949 death records and contacted next of kin to determine handedness. Note that there are many possible definitions of "left-handed." The researchers examined the effects of different definitions on the results of their analysis and found that their conclusions were not sensitive to the exact definition used. For the results presented here, people were defined to be right-handed if they wrote, drew, and threw a ball with the right hand. All others were defined to be left-handed. People were classified by gender (female or male) and handedness (left or right), and a 2 × 2 ANOVA was run with the age at death as the response variable. The F statistics were 22.36 (handedness), 37.44 (gender), and 2.10 (interaction). The following marginal mean ages at death (in years) were reported: 77.39 (females), 71.32 (males), 75.00 (right-handed), and 66.03 (left-handed).

 

(a) For each of the F statistics given, find the degrees of freedom and an approximate P-value. Summarize the results of these tests.

 

(b) Using the information given, write a short summary of the results of the study.

Answer 1

a better study might be of the presidents as their handedness is far more well known and clear. their ages also very well known HW Bush died at 94, Ford Reagan both 93, Truman 88

Garfield was ambidextrous and died young

Truman, Ford, Reagan, HW Bush, Clinton and Obama were the only left handed presidents

6 out of 47

also Jefferson and Wilson lost use of their right hands and then wrote left handed. Jefferson did seem to be ambidextrous

Garfield was assassinated in office dying at age 49, younger than any other president except JFK

major attempts to kill Truman and Reagan. only by chance did they live so long

many left handers are pressured or forced to be right handed, so asking friends what they were can be very misleading

originally there was a study showing left handed presidents died earlier, but it is now considered statistically flawed and there is no connection between handedness and age at death

similarly any statistics study claiming a connection between handedness and lifespans will be either statistically flawed or just a spurious correlation. spurious means no real cause and effect, just an accidental "connection"