Hint: We need to know how to calculate the area under the curve for the given z value using the formula 
Here, A represents the area under the normal distribution curve and CL represents the confidence level. We then get the corresponding area. Using this area value, we look up the normal distribution table for the corresponding row and column and add the two to obtain the z value. Complete step-by-step solution:Let us consider the first case for which the given confidence level is 90 percent. In this case, we need to calculate the area under the curve and it can be given as shown in the figure below. \n \n \n \n \n It can be calculated by using the formula 
Here, A represents the area under the normal distribution curve and CL represents the confidence level. Substituting the CL value as 0.90, we get
Adding and dividing by 2,
Looking for this value in the normal distribution table given below, we can see that this value lies close to the row containing 1.6 and column containing 0.05. It also lies close to the row containing 1.6 and column containing 0.04. So, we take a mean of these values to obtain the z value at this point.
Hence, the z value at the 90 percent confidence interval is 1.645.\n \n \n \n \n Let us consider the second case for which the given confidence level is 95 percent. In this case, we need to calculate the area under the curve and it can be given as shown in the figure below. \n \n \n \n \n It is calculated by using the formula 
Substituting the values,
Adding and dividing by 2,
Looking for this value in the normal distribution table given above, we can see that this value lies on the row containing 1.9 and column containing 0.06. Adding the two values,
Hence, the z value at the 95 percent confidence interval is 1.96.Let us consider the third case for which the given confidence level is 99 percent. In this case too, we need to calculate the area under the curve and it can be given as shown in the figure below. \n \n \n \n \n It is calculated by using the formula 
Substituting the values,
Adding and dividing by 2,
Looking for this value in the normal distribution table given above, we can see that this value lies on the row containing 2.5 and column containing 0.08. Adding the two values,
Hence, the z value at the 99 percent confidence interval is 2.58.Note: : It is important to take care while noting down the z value from the table, since it can be confusing and it is common to make errors while reading data from a table usually. It is important to know the concept of probability and statistics to solve this question. Answer from Vedantu Content Team on vedantu.com
Here, A represents the area under the normal distribution curve and CL represents the confidence level. We then get the corresponding area. Using this area value, we look up the normal distribution table for the corresponding row and column and add the two to obtain the z value. Complete step-by-step solution:Let us consider the first case for which the given confidence level is 90 percent. In this case, we need to calculate the area under the curve and it can be given as shown in the figure below. \n \n \n \n \n It can be calculated by using the formula Here, A represents the area under the normal distribution curve and CL represents the confidence level. Substituting the CL value as 0.90, we get Adding and dividing by 2, Looking for this value in the normal distribution table given below, we can see that this value lies close to the row containing 1.6 and column containing 0.05. It also lies close to the row containing 1.6 and column containing 0.04. So, we take a mean of these values to obtain the z value at this point. Hence, the z value at the 90 percent confidence interval is 1.645.\n \n \n \n \n Let us consider the second case for which the given confidence level is 95 percent. In this case, we need to calculate the area under the curve and it can be given as shown in the figure below. \n \n \n \n \n It is calculated by using the formula Substituting the values, Adding and dividing by 2, Looking for this value in the normal distribution table given above, we can see that this value lies on the row containing 1.9 and column containing 0.06. Adding the two values, Hence, the z value at the 95 percent confidence interval is 1.96.Let us consider the third case for which the given confidence level is 99 percent. In this case too, we need to calculate the area under the curve and it can be given as shown in the figure below. \n \n \n \n \n It is calculated by using the formula Substituting the values, Adding and dividing by 2, Looking for this value in the normal distribution table given above, we can see that this value lies on the row containing 2.5 and column containing 0.08. Adding the two values, Hence, the z value at the 99 percent confidence interval is 2.58.Note: : It is important to take care while noting down the z value from the table, since it can be confusing and it is common to make errors while reading data from a table usually. It is important to know the concept of probability and statistics to solve this question. Answer from Vedantu Content Team on vedantu.comStatistics LibreTexts
stats.libretexts.org › bookshelves › introductory statistics › statistics with technology 2e (kozak) › 12: appendix- critical value tables
12.2: Normal Critical Values for Confidence Levels - Statistics LibreTexts
January 6, 2022 - Critical values for \(Z_{c}\) created using Microsoft Excel
Coconino Community College
coconino.edu › resources › files › pdfs › academics › sabbatical-reports › kate-kozak › appendix_table.pdf pdf
Appendix: Critical Values Tables 433 Appendix: Critical Value Tables
Table A.2: Critical Values for t-Interval · Appendix: Critical Values Tables · 434 · Table A.1: Normal Critical Values for Confidence Levels · Confidence Level, C · Critical Value, zc · 99% 2.575 · 98% 2.33 · 95% 1.96 · 90% 1.645 · 80% 1.28 · Critical Values for Zc created using ...
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What is a confidence interval?
A confidence interval is a range of values that likely contains the true population parameter. For example, a 95% confidence interval means we're 95% confident the true value falls within that range. Z-scores help calculate these intervals.
z-table.com
z-table.com › 99-confidence-interval-z-score.html
99 Confidence Interval Z Score - Z SCORE TABLE
What is a Z-score?
A Z-score (or standard score) measures how many standard deviations a data point is from the mean. It's calculated as: Z = (X - μ) / σ, where X is the value, μ is the mean, and σ is the standard deviation.
z-table.com
z-table.com › 99-confidence-interval-z-score.html
99 Confidence Interval Z Score - Z SCORE TABLE
How do you use a Z-score table?
To use a Z-score table: 1) Calculate your Z-score, 2) Find the row matching the first two digits, 3) Find the column for the second decimal place, 4) The intersection gives you the probability or area under the normal curve.
z-table.com
z-table.com › 99-confidence-interval-z-score.html
99 Confidence Interval Z Score - Z SCORE TABLE
MathBlog
mathblog.com › statistics › definitions › z-score › ci › 99-to-z
99% Confidence Interval to Z-score
April 22, 2024 - This extraordinarily high level of confidence is rarely employed in everyday statistical analysis but is reserved for scenarios where the implications of uncertainty are especially critical. The Z-score for a 99.8% interval is approximately 3.09
Z Score Table
z-table.com › 99-confidence-interval-z-score.html
99 Confidence Interval Z Score - Z SCORE TABLE
You To begin our exploration, let's understand the z-score associated with a 99% confidence interval. The z-score represents the number of standard deviations a given value is from the mean of a distribution. For a 99% confidence interval, the z-score is approximately 2.576.
Homework.Study.com
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Find the critical z-score value for the 99% confidence level. | Homework.Study.com
Z-scores or standard scores are obtained by taking the deviations of the values from their means and dividing them by their standard deviations. These are widely used in z-tests, computing the confidence intervals when the population standard deviation is known, in principal component analysis, etc.
Brainly
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[FREE] What is the critical value z for constructing a 99% confidence interval? - brainly.com
The critical value z for constructing a 99% confidence interval is approximately ±2.576. This value indicates the number of standard deviations away from the mean to capture the central 99% of a normal distribution.
Stats4stem
stats4stem.org › introduction-to-confidence-intervals
Introduction to Confidence Intervals
One Proportion, One Sample Mean Z, One Sample Mean T, Matched Pairs, etc. ... These conditions vary depending on the type of confidence interval you are constructing. Step 3: Construct the Interval (Apply the Formula) Basic Formula: point estimate +/- (critical value) x (standard error)
Fiveable
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Critical Value (z-score) - (AP Statistics) - Vocab, Definition, Explanations | Fiveable | Fiveable
To find the critical value for ... normal distribution table or use statistical software to find the z-score corresponding to an area of 0.995 (1 - 0.005)....
Crafton Hills College
craftonhills.edu › current-students › tutoring-center › mathematics-tutoring › distribution_tables_normal_studentt_chisquared.pdf pdf
Confidence Interval Critical Values, zα/2 Level of Confidence
Confidence Interval Critical Values, zα/2 · Level of Confidence · Critical Value, z α/2 · 0.90 or 90% 1.645 · 0.95 or 95% 1.96 · 0.98 or 98% 2.33 · 0.99 or 99% 2.575 · Hypothesis Testing Critical Values · Level of Significance, α · Left-Tailed · Right-Tailed ·
Studocu
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[Solved] to calculate a 99 confidence interval using a normal distribution - Principles of Statistics I (ECON 261) - Studocu
February 22, 2024 - This value is the number of standard ... for common confidence levels: So, for a 99% confidence interval, you would use a z* value of 2.576....
Brainly
brainly.com › mathematics › college › the critical value [tex]$\left(z^*\right)$[/tex] used for a [tex]$99.5 \%$[/tex] confidence interval for a sample mean when the population standard deviation is known is 2.576
[FREE] The critical value $\left(Z^\right)$ used for a $99.5 \%$ confidence interval for a sample mean when the - brainly.com
Finding the Critical Value: To find the critical value Z∗ for this confidence level, we look for the Z-value that corresponds to a cumulative probability of 0.9975 (since we add the 0.0025 from one tail).
Sage Calculator
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Critical Z Values Calculator - Sage Calculator
July 3, 2025 - 5. How do I use Z value in confidence intervals? CI = x̄ ± Z * (σ/√n) 6. What Z value do I use for a 99% confidence level?
Statistics How To
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Critical Values: Find a Critical Value in Any Tail - Statistics How To
December 31, 2024 - Divide Step 2 by 2 (this is called “α/2”). So: 0.10 = 0.05. This is the area in each tail. Subtract Step 3 from 1 (because we want the area in the middle, not the area in the tail): So: 1 – 0.05 = .95. Look up the area from Step in the z-table. The area is at z=1.645...
Quora
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What is the value of Z for a 99 confidence interval? - Quora
Answer (1 of 4): The first answer may confuse some people in multiple ways. 1st , I understand that to save paper in many old text books. Only half of the z-table is provided, the positive half. Also, to save a little ink, in many textbook 0.5 or 1/2 was subtracted from each value. So the z ...
Omni Calculator
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99% Confidence Interval Calculator
June 11, 2024 - The z-score for a two-sided 99% confidence interval is 2.807, which is the 99.5-th quantile of the standard normal distribution N(0,1).
Statology
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How to Find Z Alpha/2 (za/2)
November 4, 2020 - α = 0.1), the z critical value is 1.645. For a test using a 95% confidence level (e.g. α = 0.05), the z critical value is 1.96. For a test using a 99% confidence level (e.g.