For a standard normal distribution, if [tex]\( P(z \leq a) = 0.7116 \)[/tex], what is the value of [tex]\( P(z \geq a) \)[/tex]?

A. 0.2116
B. 0.2884
C. 0.7116
D. 0.7884



Answer :

To find the value of [tex]\( P(z \geq a) \)[/tex] for a standard normal distribution, we need to use the properties of the cumulative distribution function (CDF) and the complementary probability.

Given:
[tex]\[ P(z \leq a) = 0.7116 \][/tex]

The probability [tex]\( P(z \leq a) \)[/tex] represents the area under the standard normal curve to the left of [tex]\( a \)[/tex]. The total area under the standard normal distribution curve is 1.

The complementary probability [tex]\( P(z \geq a) \)[/tex] represents the area under the standard normal curve to the right of [tex]\( a \)[/tex]. We can find this complementary probability by subtracting [tex]\( P(z \leq a) \)[/tex] from 1.

[tex]\[ P(z \geq a) = 1 - P(z \leq a) \][/tex]

Substituting the given value:
[tex]\[ P(z \geq a) = 1 - 0.7116 \][/tex]

[tex]\[ P(z \geq a) = 0.2884 \][/tex]

Therefore, the value of [tex]\( P(z \geq a) \)[/tex] is:

[tex]\[ 0.2884 \][/tex]

So the correct answer is:

[tex]\[ \boxed{0.2884} \][/tex]

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