SAT scores are used by colleges and universities to evaluate undergraduate applicants. The test
scores are normally distributed. A random sample of 65 student scores has a mean of 1489 and
standard deviation of 306.
Find the 95% confidence interval for the population mean based on this sample and round to
two decimal places.

Respuesta :

Using the t-distribution, it is found that the 95% confidence interval for the population mean is (1413.18, 1564.82).

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 65 - 1 = 64 df, is t = 1.9977.

The parameters of the interval are given as follows:

[tex]\overline{x} = 1489, s = 306, n = 65[/tex].

Hence, the bounds of the interval are given by:

[tex]\overline{x} - t\frac{s}{\sqrt{n}} = 1489 - 1.9977\frac{306}{\sqrt{65}} = 1413.18[/tex]

[tex]\overline{x} + t\frac{s}{\sqrt{n}} = 1489 + 1.9977\frac{306}{\sqrt{65}} = 1564.82[/tex]

The 95% confidence interval for the population mean is (1413.18, 1564.82).

More can be learned about the t-distribution at https://brainly.com/question/16162795