find the sum of the area under the standard normal curve to the left of z = - 1.25 and the right of z = 1.25.

The standard normal curve is symmetric, so the area to the left of z = -1.25 is the same as that to the right of z = 1.25. Find one or the other and double your result.

To the left of 1.25: normalcdf(-1000, 1.25) = 0.1056, or 0.106. Double that; result is 0.212 (answer).

Answer Link

fichoh fichoh · Answer 2 · 2021-10-26T20:25:51+02:00

The area under the standard normal curve gives the standard normal probability of z value which falls within the area. Hence, the sum of the area to the left of z = -1.25 and the right of z = 1.25 is 0.2113

Using a normal distribution table :

P(Z < - 1.25) = 0.10565

P(Z > 1.25) = 1 - P(Z < 1.25)

P(Z > 1.25) = 1 - 0.89435

P(Z > 1.25) = 0.10565

The sum of the area to the left z = - 1.25 and right ; z = 1.25 is the sum of the probabilities calculated :

P(Z < - 1.25) + P(Z > 1.25)

0.10565 + 0.10565 = 0.2113

Therefore, the sum of the areas to the left and right is 0.2113.

Learn more :https://brainly.com/question/1993757