Answer :
Using the t-distribution, as we have the standard deviation for the sample, the 95% confidence interval is (71.63, 84.36).
What is a t-distribution confidence interval?
The confidence interval is:
[tex]\overline{x} \pm t\frac{s}{\sqrt{n}}[/tex]
In which:
- [tex]\overline{x}[/tex] is the sample mean.
- t is the critical value.
- n is the sample size.
- s is the standard deviation for the sample.
The critical value, using a t-distribution calculator, for a two-tailed 95% confidence interval, with 4 - 1 = 3 df, is t = 3.1824.
The parameters are given as follows:
[tex]\overline{x} = 78, s = 10, n = 4[/tex]
Hence, the bounds of the interval are given by:
[tex]\overline{x} - t\frac{s}{\sqrt{n}} = 78 - 3.1824\frac{10}{\sqrt{4}} = 71.63[/tex]
[tex]\overline{x} + t\frac{s}{\sqrt{n}} = 78 + 3.1824\frac{10}{\sqrt{4}} = 84.36[/tex]
The 95% confidence interval is (71.63, 84.36).
More can be learned about the t-distribution at https://brainly.com/question/16162795
Answer:
(62.09, 93.91)
Step-by-step explanation:
The correct answer on Khan
