Respuesta :
Using the t-distribution, it is found that the correct interpretation is:
b. Based on the sample data, with 90% confidence, the ISP can conclude that the true population mean daily usage time is between 297.75 minute(s) and 334.75 minute(s).
We can find the standard deviation for the sample, which is why the t-distribution is used to solve this question.
- We are given a sample size of [tex]n = 64[/tex].
Using a calculator, we find that:
- The sample mean is [tex]\overline{x} = 316.25[/tex]
- The sample standard deviation is [tex]s = 35.68[/tex]
The confidence interval is:
[tex]\overline{x} \pm t\frac{s}{\sqrt{n}}[/tex]
The critical value, using a t-distribution calculator, for a two-tailed 90% confidence interval, with 12 - 1 = 11 df, is t = 1.7959.
Then:
[tex]\overline{x} - t\frac{s}{\sqrt{n}} = 316.25 - 1.7959\frac{35.68}{\sqrt{12}} = 297.75[/tex]
[tex]\overline{x} + t\frac{s}{\sqrt{n}} = 316.25 + 1.7959\frac{35.68}{\sqrt{12}} = 334.75[/tex]
From the confidence interval, we can infer about the population mean, hence, the correct option is:
b. Based on the sample data, with 90% confidence, the ISP can conclude that the true population mean daily usage time is between 297.75 minute(s) and 334.75 minute(s).
A similar problem is given at https://brainly.com/question/15180581
