Find the critical value $z _ { \alpha / 2 }$ needed to construct a(n) 97% confidence interval.
A) 2.17
B) 1.88
C) 2.75
D) 1.92

Question

Quizplus · Accepted Answer

To find the critical value $z_{\alpha/2}$ we use a standard normal distribution table or calculator. For a 97% confidence interval, we need to find the value that leaves 1% in both tails of the distribution. This gives us an area of 0.5% in each tail. Looking at the table, the closest value to this area is 0.4950, which corresponds to a z-score of 2.17. Therefore, the critical value needed is 2.17.

Find the Critical Value zα/2z _ { \alpha / 2 }zα/2​

Find the Critical Value $z _ { \alpha / 2 }$