Question

Z* for 90% confidence is ________. (hint: use z-table c, or software.) answer to three decimal places x.xxx

Answer 1

We have to find the z critical value at 100% - 90% = 10% level of significance.

Since the normal distribution has two tails, we therefore, need to divide the significance level into two tails with each tail having area of 5%.

Now using the standard normal table, the z critical is:

`z=\pm1.645`