After buying many helium balloons only to see them deflatewithin a couple of days, Erin and Jenna decided to test ifhelium-filled balloons deflate faster than air-filled balloons. Tofind out, they bought 60 balloons of the same type and randomlydivided them into two piles of 30, filling the balloons in thefirst pile with helium and the balloons in the second pile withair. Then, they measured the circumference of each balloonimmediately after being filled and again three days later. Theaverage decrease in the circumference of the helium-filled balloonswas 26.5 cm with a standard deviation of 1.92 cm. The averagedecrease of the air-filled balloons was 2.1 cm with a standarddeviation of 2.79 cm.
a. How many degrees of freedom are appropriate to constructa confidence interval for the difference in ”decrease ofcircumference” for the balloons filled with helium and the balloonsfilled with air?
b. What is the margin of error for a 95% confidenceinterval for the difference in ”decrease of circumference” for theballoons filled with helium and the balloons filled with air?
c. Construct the confidence interval for the difference.Enter the number with the larger absolute value.
D. What sample size would be necessary (n1 = n2) for amargin of error of .5 inches?
After buying many helium balloons only to see them deflate within a couple of days, Erin and Jenna decided to test if he
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After buying many helium balloons only to see them deflate within a couple of days, Erin and Jenna decided to test if he
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