The upper limit of the 90% confidence interval for $\mu$ , given that n = 64, $\bar { x }$ = 70 and $\sigma$ = 20, is 65.89.

Question

Quizplus · Accepted Answer

We can use the formula for a 90% confidence interval for the population mean:

$$\bar{x} \pm z_{\alpha/2} \frac{\sigma}{\sqrt{n}}$$

Plugging in the given values, we get:

$$70 \pm z_{0.05} \frac{20}{\sqrt{64}}$$

Simplifying gives:

$$70 \pm 2.262 $$

The upper limit of this interval is:

$$70 + 2.262 = 72.262$$

Therefore, the answer is B, since 72.262 is greater than 65.89.

The Upper Limit of the 90% Confidence Interval For μ\muμ , Given That N = 64