A matrix is a rectangular array of numbers arranged in rows and columns. The inverse of a matrix is a matrix that, when multiplied by the original matrix, yields the identity matrix. The identity matrix is a matrix with ones on the diagonal and zeros elsewhere.

Finding the inverse of a matrix can be tedious if you try to do it by hand, especially for larger matrices. Fortunately, most graphing calculators, including the TI-83 Plus, have a built-in function for finding the inverse of a matrix.

Following are the steps to find the inverse of a matrix on the TI-83 Plus:

- Press the “2nd” button, located in the top left corner of the calculator, followed by the “x^-1” button, which is located directly below the “2nd” button. It will take you to the “Matrix” menu.
- Use the arrow keys to navigate to the matrix you want to invert. You can also use the up and down arrow keys to move between rows and the left and right arrow keys between columns. Once you have selected the matrix you want to invert, press “Enter” to select it.
- Press the “x^-1” button again to indicate that you want to take the matrix inverse.
- Press “Enter” to calculate the inverse. The inverse of the matrix will be displayed on the calculator screen.

## How do you find the t value?

First you need to determine the test statistic for your hypothesis test, to find the t-value. The test statistic for a t-test is calculated as follows:

t = (sample mean – hypothesized mean) / (standard error of the mean)

Where the sample mean is the average of your sample, the hypothesized mean is the value you are testing (i.e., the null hypothesis), and the standard an error of the mean is the sample’s standard deviation divided by the sample size’s square root.

After calculating the test statistic, you can determine the t-value by comparing it to the t-distribution with n-1 degrees, where n is the sample size. The t-distribution is a probability distribution that describes the distribution of the t-statistic under the null hypothesis.

The t-value represents the number of standard errors that the test statistic is from the hypothesized value. It is calculated as:

T-value = (test statistic – hypothesized value) / standard error of the test statistic

For example, suppose you are testing the hypothesis that the mean weight of a population of cats is 10 pounds. You collect a sample of 25 cats and find that the mean sample weight is 9.5 pounds, and the sample standard deviation is 1 pound. The standard error of the mean is calculated as follows:

Standard error of the mean = standard deviation / square root of the sample size = 1 / sqrt(25) = 0.2 pounds

The test statistic is calculated as follows:

Test statistic = (sample mean – hypothesized mean) / standard error of the mean = (9.5 – 10) / 0.2 = -2.5

Considering a two-tailed test with a significance level of 0.05 and 24 degrees of freedom (i.e., 25-1), the t-value can be found using a t-table or calculator with a t-distribution function. The t-value for a two-tailed test with 24 degrees of freedom and a significance level of 0.05 approximately ±2.064.

Thus, the t-value in this example is -2.5, which is greater than -2.064, indicating that the test statistic falls within the rejection region. Therefore, you would reject the null hypothesis and suppose that the mean weight of the population of cats is less than 10 pounds.

## What is the difference between TI-83 and TI-83+?

The TI-83 and TI-83 Plus are graphing calculators developed by Texas Instruments, but the two models have some key differences.

**Memory:** The TI-83 Plus has more memory than the TI-83. The TI-83 has 32 kilobytes of RAM, while the TI-83 Plus has 160 kilobytes of ROM and 24 kilobytes of RAM.

**Speed:** The TI-83 Plus is faster than the TI-83. The TI-83 Plus has a clock speed of 6 MHz, while the TI-83 has a clock speed of 4 MHz

**Display:** The TI-83 Plus has a slightly larger screen than the TI-83. The TI-83 Plus has a 96×64 pixel display, while the TI-83 has a 64×96 pixel display. The TI-83 Plus also has a higher contrast display, which makes it easier to read in different lighting conditions.

**USB Connectivity:** The TI-83 Plus has a USB port, while the TI-83 has only a serial port. It allows the TI-83 Plus to connect to computers more easily and transfer data faster.

**Features:** The TI-83 Plus has some additional features that the TI-83 does not have. For example, the TI-83 Plus can display graphs in polar and sequence modes and perform symbolic manipulation with the optional Computer Algebra System (CAS) module.

## Conclusion: How to find invt on ti-83 plus?

With its larger memory, faster processor, and additional features, the TI-83 Plus significantly improved over its predecessor, the TI-83. The TI-83 Plus calculator offers powerful tools for performing statistical analysis, including finding the invT function through the T-INV functions in the DISTR menu. Using the T-INV function, users can quickly and easily find the t-value for a given probability and degrees of freedom. It is a valuable tool for hypothesis testing and confidence interval calculations. Overall, the TI-83 Plus is essential for students and professionals who must perform statistical analysis regularly.