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Express the probabilities as decimals for the given events on the standard normal distribution (z-scores).

P(z > 1.38):
A. 0.0848
B. 0.1611
C. 0.4162
D. 0.9152

P(1.23 < z < 3.24):
A. 0.3121
B. 0.3669
C. 0.4821
D. 0.5783

P(z < -0.42):
A. 0.3365
B. 0.3452
C. 0.4157
D. 0.6616

P(-2.64 < z < 1.64):
A. 0.4382
B. 0.7064
C. 0.8212
D. 0.9443

P(z < 3.04):
A. 0.9950
B. 0.8564
C. 0.8202
D. 0.9988

P(0 < z < 2):
A. 0.3085
B. 0.4582
C. 0.4893
D. 0.7357

P(z > -2.43):
A. 0.9929
B. 0.8856
C. 0.3264
D. 0.7169

User Jayson H
by
7.8k points

1 Answer

4 votes

Final answer:

The probabilities for the various events on the standard normal distribution were calculated using z-scores and a z-table, with several options being close to or exactly the calculated values after comparing area under the curve.

Step-by-step explanation:

The probability is represented by the area under the normal curve. To find the probability, we calculate the z-score and look up the z-score in the z-table under the z-column. Most z-tables show the area under the normal curve to the left of z. If you have a z-table that shows the area to the right, you can subtract the area to the left from 1 to find the area to the right. This can be used to answer probability questions related to standard normal distribution.

  • P(z > 1.38) = 1 - Area to the left of z = 1 - 0.9162 = 0.0838 (Option A is close but seems to be a typo).
  • P(1.23 < z < 3.24) = Area to the left of z = 3.24 - Area to the left of z = 1.23 = 0.9993 - 0.8907 = 0.1086 (None of the given options are correct).
  • P(z < -0.42) = Area to the left of z = -0.42 = 0.3372 (Option A is close but also seems to be incorrect).
  • P(-2.64 < z < 1.64) = Area to the left of z = 1.64 - Area to the left of z = -2.64 = 0.9495 - 0.0041 = 0.9454 (Option D is the closest).
  • P(z < 3.04) = Area to the left of z = 3.04 = 0.9988 (Option D is correct).
  • P(0 < z < 2) = Area to the left of z = 2 - Area to the left of z = 0 = 0.9772 - 0.5 = 0.4772 (None of the given options are correct).
  • P(z > -2.43) = 1 - Area to the left of z = -2.43 = 1 - 0.0075 = 0.9925 (Option A is closest to the correct value).
User EFreak
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8.0k points