Answer :
Answer:
The 80% confidence interval for difference between two means is (0.85, 1.55).
Step-by-step explanation:
The (1 - α) % confidence interval for difference between two means is:
[tex]CI=(\bar x_{1}-\bar x_{2})\pm t_{\alpha/2,(n_{1}+n_{2}-2)}\times SE_{\bar x_{1}-\bar x_{2}}[/tex]
Given:
[tex]\bar x_{1}=M_{1}=6.1\\\bar x_{2}=M_{2}=4.9\\SE_{\bar x_{1}-\bar x_{2}}=0.25[/tex]
Confidence level = 80%
[tex]t_{\alpha/2, (n_{1}+n_{2}-2)}=t_{0.20/2, (5+5-2)}=t_{0.10,8}=1.397[/tex]
*Use a t-table for the critical value.
Compute the 80% confidence interval for difference between two means as follows:
[tex]CI=(6.1-4.9)\pm 1.397\times 0.25\\=1.2\pm 0.34925\\=(0.85075, 1.54925)\\\approx(0.85, 1.55)[/tex]
Thus, the 80% confidence interval for difference between two means is (0.85, 1.55).
