In July 2013, cnet.com listed the battery life (in hours) and luminous intensity (i. e., screen brightness, in cd/m2) for a sample of tablet computers. We want to know if screen brightness is associated with battery life.
(reviews.cnet.com/8301-19736_(reviews.cnet.com/8301-19736_7-20080768-251/cnet-updates-tablet-test-results/?251/cnet-updates-tablet-test-results/? tag= contentBody; contentHighlights)

a) How many tablet computers were tested?
b) Are the conditions for inference satisfied? Explain.
c) Is there evidence of an association between maximum brightness of the screen and battery life? Test an appropriate hypothesis and state your conclusion.
d) Is the association strong? Explain.
e) What is the equation of the regression line?
f) Create a 95% confidence interval for the slope of the true line.
g) Interpret your interval in this context.

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Dependent variable is Video battery life (in hours) R-squared 4.82% s=1.946 with 69-2=67 degrees of freedom Variable Intercept 6.21108 Brightness 0.00486 Coeff SE(Coeff) t-Ratio P-Value 6.46 6.0001 1.84 0.0699 0.9609 0.0026 14 12 10 100 200 300 400 500 600 Maximum Brightness (in cdim*2) 7.5 8.0 8.5 9.0 Predicted Battery Life Nomal Scores