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91Ó°ÊÓ

Find the indicated probability of the standard normal random variable \(Z\). $$P(Z<1.93)$$

Short Answer

Expert verified
\( P(Z < 1.93) = 0.9732 \)

Step by step solution

01

- Understand the Standard Normal Distribution

The standard normal distribution is a normal distribution with a mean of 0 and a standard deviation of 1. It is often represented by the variable \(Z\).
02

- Identify the Given Z-value

We need to find the probability that the standard normal random variable \(Z\) is less than 1.93, denoted as \(P(Z < 1.93)\).
03

- Use the Z-table

Locate the value 1.93 in the Z-table, which provides the cumulative probability for Z-values. The Z-table shows that \(P(Z < 1.93) = 0.9732\). This means the probability that \(Z\) is less than 1.93 is 0.9732.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Cumulative Probability
Cumulative probability refers to the probability that a random variable takes on a value less than or equal to a certain value. In the context of the standard normal distribution, we talk about the probability that the value of the random variable Z is less than or equal to a given Z-value. For example, if we're interested in finding the cumulative probability for Z=1.93, we want to know the probability that Z is less than or equal to 1.93. This cumulative probability is essentially the area under the standard normal curve to the left of the Z-value. Remember, cumulative probabilities increase as Z-values increase.
Z-table
A Z-table is a chart that shows the cumulative probabilities of the standard normal distribution. It helps us find probabilities for specific Z-values. To use the Z-table:
  • Locate the Z-value in the left-most column and top-most row.
  • Combine these to find the cumulative probability.
For instance, in our problem, we need to find the Z-value 1.93. By locating the Z-value 1.9 in the left column and 0.03 in the top row and intersecting them, we find that the cumulative probability is 0.9732. This tells us that the probability that Z is less than 1.93 is 0.9732. Keep in mind that Z-tables typically provide the probability for Z-values less than the chosen value.
Probability Calculation
To calculate the probability of a standard normal random variable Z being less than a certain value, we use the Z-table. Here are the steps:
  • First, identify the Z-value you're interested in. In our case, it is 1.93.
  • Next, use the Z-table to find the cumulative probability corresponding to 1.93.
  • The Z-table tells us that the cumulative probability for Z being less than 1.93 is 0.9732.
Thus, we have calculated that the probability of Z being less than 1.93 is 0.9732, meaning there's a 97.32% chance that Z will fall below 1.93 in a standard normal distribution.

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