Use the following to answer the questions below:
As part of a course project, a statistics student surveyed random samples of 50 student athletes and 50 student non-athletes at his university, with the goal of comparing the heights of the two groups. His summary statistics are displayed in the provided table.

-Construct a 99% confidence interval for the difference in mean heights between student athletes and non-athletes at this university. Use two decimal places in your margin of error.
A) -0.40 to 3.76
B) -0.32 to 3.68
C) -0.16 to 3.20
D) -0.20 to 3.56

Question

Use the following to answer the questions below:
As part of a course project, a statistics student surveyed random samples of 50 student athletes and 50 student non-athletes at his university, with the goal of comparing the heights of the two groups. His summary statistics are displayed in the provided table.
 
-Construct a 99% confidence interval for the difference in mean heights between student athletes and non-athletes at this university. Use two decimal places in your margin of error.
A) -0.40 to 3.76 
B) -0.32 to 3.68 
C) -0.16 to 3.20 
D) -0.20 to 3.56

Quizplus · Accepted Answer

n = 50 - this is a reasonably large sample size (and no real reason to suspect that heights are drastically skewed), so we can use a t-distribution to construct the confidence interval.
n = 50, so df = 49 and thus t* = 2.68
(68.96 - 67.28) ± 2.68 11eeb2d3_8e0e_9cf6_b9aa_6537404c085d_TBW1049_00 1.68 ± 2.68(0.7750368)
1.68 ± 2.08
-0.4 to 3.76

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