A regression analysis was performed and the summary output is shown below. Regression Statistics
Multiple R0.724923428
R Square0.5255139760
Adjusted R Square0.507940420
Standard Error8.436229191
Observations85
ANOVA
dfdfMSMSFFSignificance FF
Regression336384.7312128.24429.90374.0941E-13
Residual815764.76771.170
Total8412,149.498
Step 1 of 2:
How many independent variables are included in the regression model?
Step 2 of 2:
Which measure is appropriate for determining the proportion of variation in the dependent variable explained by the set of independent variable(s) in this model?

I'll pick variables and set up a system. In this case, I'll use "p" for "the plane's speedometer reading (apparent speed)" and "w" for "the windspeed". When the plane is going "with" the wind (when it has a "tailwind"), the two speeds will add together; when the plane is going "against" the wind (when it has a "headwind"), the windspeed will be subtracted from the plane's speedometer reading (that is, from the engines' actual output). 

In each case, the "distance" equation will be "(the combined speed) times (the time at that speed) equals (the total distance travelled)": 

with the wind: (p + w)(2.33) = 1340 

against the wind: (p – w)(2.833) = 1340 

Rather than multiply through, I notice that, if I divide off the 2.33 and the 2.833, I'll have a system that's already set for solving by addition 

p + w = 575.1 
p – w = 472.99 

Then, by adding down, 2p = 1048 so p = 524, and w must then be 51.1 

wind speed is 51.1 mph