A Psychologist Has Performed the Following Experiment Can She Infer at the 5% Significance Level That There

Essay

A psychologist has performed the following experiment. For each of 10 sets of identical twins who were born 30 years ago, she recorded their annual incomes according to which twin was born first. The results (in $000) are shown below. $$\begin{array} { | c | c | c | } \hline \text { Twin set } & \text { First born } & \text { Second born } \\\hline 1 & 32 & 44 \\\hline 2 & 36 & 43 \\\hline 3 & 21 & 28 \\\hline 4 & 30 & 39 \\\hline 5 & 49 & 51 \\\hline 6 & 27 & 25 \\\hline 7 & 39 & 32 \\\hline 8 & 38 & 42 \\\hline 9 & 56 & 64 \\\hline 10 & 44 & 44 \\\hline\end{array}$$ Can she infer at the 5% significance level that there is a difference in income between the twins?