Final Answer:
The assumption required to use the formula (nzx/2/σα±) for a confidence interval estimate of the population mean is that the population is normally distributed.
Step-by-step explanation:
The formula (nzx/2/σα±) is based on the Central Limit Theorem, which asserts that the distribution of sample means becomes approximately normal, regardless of the original population distribution, given a sufficiently large sample size. This implies that for accurate results, the underlying population should exhibit a normal distribution. If the population is not normally distributed, the validity of the confidence interval estimate may be compromised.
Normality is crucial because it ensures that the sampling distribution of the mean is also normal, facilitating the application of statistical methods. Deviations from normality can lead to inaccurate confidence intervals. Therefore, when employing this formula, it is essential to assess the normality assumption through techniques like histograms or statistical tests.