Z Critical Value on a TI-84 Calculator: A Comprehensive Guide
Z Critical Value on a TI-84 Calculator, When conducting a hypothesis test, one key metric you’ll encounter is the Z critical value.
This value helps determine whether the results of your test are statistically significant.
If you’re using a TI-84 calculator, finding the Z critical value is a straightforward process.
In this guide, we’ll walk you through the steps to do so.
What is a Z Critical Value?
A Z critical value is a point on the Z distribution that corresponds to a specific confidence level.
It essentially helps in decision-making by indicating if the test statistic falls within the range of statistical significance.
If the absolute value of the test statistic exceeds the Z critical value, the results of your test are deemed statistically significant.
Steps to Find the Z Critical Value on a TI-84 Calculator
To find the Z critical value on a TI-84 calculator, you will use the invNorm function.
This function calculates the inverse of the standard normal cumulative distribution.
Here’s how you can do it:
1. Access the invNorm Function
- Press the
2ndbutton on your TI-84 calculator. - Then press
VARSto open theDISTRmenu. - Select
invNorm()from the menu.
2. Input the Parameters
The invNorm function requires the following parameters:
- Probability: This is the significance level (α) of your test.
- Mean (μ): This is the population mean, which for standard normal distribution is 0.
- Standard Deviation (σ): This is the population standard deviation, which for standard normal distribution is 1.
The syntax for the invNorm function is: invNorm(probability, μ, σ)
3. Calculate the Z Critical Value
Here are examples for different types of tests:
- Left-Tailed Test: For a left-tailed test with α = 0.05, enter
invNorm(.05, 0, 1). The calculator will return approximately-1.6449. - Right-Tailed Test: For a right-tailed test with α = 0.10, enter
invNorm(1-.10, 0, 1). The result will be approximately1.2816. - Two-Tailed Test: For a two-tailed test with α = 0.05, enter
invNorm(.05/2, 0, 1). The calculator will return two critical values: approximately-1.96and1.96.
Conclusion
Finding the Z critical value is a user-friendly process once you understand the steps and parameters involved.
Whether you’re conducting left-tailed, right-tailed, or two-tailed tests, the invNorm function simplifies the process, allowing you to efficiently determine the critical values necessary for your hypothesis testing.
This knowledge will enable you to make more accurate and informed decisions based on your statistical analysis.
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