Tail-Feather Length in Birds Is Sometimes a Sexually Dimorphic Trait;

Multiple Choice

Tail-feather length in birds is sometimes a sexually dimorphic trait; that is, the trait differs substantially for males and for females of the same species. Researchers studied the relationship between tail-feather length (measuring the R1 central tail feather) and weight in a sample of 20 male long-tailed finches raised in an aviary. The data are displayed in the scatterplot below, followed with software output about the least-squares regression model of feather length as a function of weight.
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\begin{array}{l}\begin{array} { l l r } \hline &\text {Coefficients }&\text {Standard Error }\\\hline\text {Intercept }&35.7379 & 21.0523 \\\text { Bird-weight}&2.8299 & 1.2811\\\hline\text {R Square }&0.2133\\\text {Standard Error }&\ 10.5270\\end{array}\end{array} What is the margin of error for a 95% confidence interval for the true population slope β in this linear regression model?

A) 1.28
B) 2.10
C) 2.51
D) 2.69