Answer:
(2.880, 11.320)
Step-by-step explanation:
Keep in mind the formula for a 2-sample t-interval.
t = x1 - x2 ± t* [tex]\sqrt{\frac{s1^{2}}{n1} +\frac{s2^{2}}{n2} }[/tex]
First calculate df the degrees of freedom and t* the critical t.
df = 23.24 (from technology: STAT->TEST->0)
t* = invt(.975, 23.24) = 2.067
Now plug them in and solve.
t = x1 - x2 ± t* [tex]\sqrt{\frac{s1^{2}}{n1} +\frac{s2^{2}}{n2} }[/tex]
= 29.7 - 22.6 ± 2.067[tex]\sqrt{\frac{3^{2}}{29} +\frac{9^{2}}{21} }[/tex]
= 7.1 ± 4.220
= (2.880, 11.320)
