Can anyone help me with statistics homework? I would be forever grateful. Thank you. Which of the following is the number Za/2 needed the construction of a confidence interval when the level of confidence is 80%?

Jan is just trying to be funny!

Find Z_α/2 for 80% confidence.

80% written as a decimal is 0.80.

1 – 0.80 = 0.20 = α and α/2 = 0.20/2 = 0.10

Not one of your choices, but I am rusty!

You might have to check your z table with that 0.10.