Answer:
c. (10.1, 15.7)
Step-by-step explanation:
The calculation of the 95% confidence interval is shown below:
Given that
n = sample = 14
average = [tex]\bar x[/tex] = 12.9
Standard deviation = s = 4.9
Based on the above information
[tex]\alpha = 1 -0.95 = 0.05[/tex]
n - 1 = 14 - 1 = 13
[tex]t_{\alpha}\ value = 2.16[/tex]
Now the 95% confidence interval is
[tex]= \bar x + \pm\ t \times \frac{s}{\sqrt{n} } \\\\= 12.9 \pm 2.16 \times \frac{4.9}{\sqrt{14} } \\\\= 12.9 \pm 2.8287[/tex]
= (10.1, 15.7)
hence, the correct option is c.
