Consider the following. (Give your answers correct to two decimal places.)

(a) Determine the value of the confidence coefficient z(á/2) for 1 - á = 0.87.
=.44 my answer .

(b) Determine the value of the confidence coefficient z(á/2) for 1 - á = 0.91.
=.46 my answer

To determine the value of the confidence coefficient z(á/2) for a given value of 1 - á, we need to use a standard normal distribution table or calculator.

(a) For 1 - á = 0.87, we want to find the value of z(á/2).
To do this, we first find the corresponding area in the standard normal distribution for 1 - á = 0.87. Since the area under the curve is symmetric, we can find the area to the left of the z-score and then subtract it from 1.

Using a standard normal distribution table or calculator, we find that the area to the left of z = 1.15 is approximately 0.8749. Subtracting this from 1, we get 1 - 0.8749 = 0.1251.

Since the confidence level is divided into two tails, we need to divide this remainder by 2. 0.1251 / 2 = 0.0625.

Now, we need to find the z-score corresponding to an area of 0.0625 in the standard normal distribution table. Finding the closest value, we see that z ≈ -1.96.

Therefore, the value of the confidence coefficient z(á/2) for 1 - á = 0.87 is approximately -1.96.

(b) Using the same process, for 1 - á = 0.91, we want to find the value of z(á/2).

Finding the area to the left of z = 1.34 is approximately 0.9099. Subtracting this from 1, we get 1 - 0.9099 = 0.0901.

Dividing this remainder by 2, we get 0.0901 / 2 = 0.0451.

Using the standard normal distribution table, the z-score corresponding to an area of 0.0451 is approximately -1.75.

Therefore, the value of the confidence coefficient z(á/2) for 1 - á = 0.91 is approximately -1.75.