7. Sampling Distributions & Confidence Intervals: Mean

Find $\alpha$ for a 90% confidence interval.

Make a 90% confidence interval for a parameter, y, with point estimate $ŷ=-1.5$, & margin of error $E=3.25$.

Find the critical value, $z_{\frac{\alpha }{2}}$, for a 80% confidence interval.

Which of the following is the correct critical value $z*$ for a confidence level of $70\%$ in a standard normal distribution?