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For the standard normal distribution, find the probabilities:

(1) P (z < 1.2)
(2) ₽ (z > 0.7)
(3) P (- 0.2 < z < 1.3)

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1 Answer

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Probabilities in the standard normal distribution are found using the Z-table: (1) 0.8849, (2) 0.7580, (3) 0.6293.

To find probabilities in the standard normal distribution, we refer to the Z-table, which provides the cumulative probability up to a certain Z-score.

1. P(z < 1.2) :

Using the Z-table, we find the probability that a randomly selected value from a standard normal distribution is less than 1.2. The Z-table indicates this probability as approximately 0.8849.

2. P(z > 0.7) :

Similarly, looking up the Z-score of 0.7 in the table and subtracting it from 1 gives the probability that a value is greater than 0.7. The result is approximately 0.7580.

3. P(-0.2 < z < 1.3) :

By finding the cumulative probabilities for Z-scores of -0.2 and 1.3 and subtracting, we obtain the probability that a value falls between -0.2 and 1.3. The result is approximately 0.6293.

In summary, for the standard normal distribution:

(1) P(z < 1.2) is approximately 0.8849.

(2) P(z > 0.7) is approximately 0.7580.

(3) P(-0.2 < z < 1.3) is approximately 0.6293.

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