**The Inverse Normal Probability Distribution Function** **invNorm()** i**s used to find z score from the percentile on TI-84 plus calculator.**

**invNorm(probability, μ, σ)**

where:

**probability:**the given percentile**μ:**population mean**σ:**population standard deviation

Note: Finding the Z-score indicates that the given distribution is a standard normal distribution with a mean of 0 and a standard deviation as 1

## Using the invNorm function on TI 84 plus

The following steps will guide us on how to calculate the Z-Score from Percentile on TI-84 plus Calculator:

- Press “
**2nd**” and then press “**VARS**”.This will take you to a**DISTR**screen. - Select “
**invNorm**” i.e 3rd option, and then press “ENTER” to bring up the invNorm wizard screen. - Enter the desired percentile as a decimal next to the word area followed by 0 for mean and 1 for standard deviation. For example, to find the z-score associated with the 95th percentile, type 0.95,0,1.
- Type a closing parenthesis “)” and then press ENTER.

Using the TI-84 Plus calculator will calculate the z-score associated with the given percentile.

Let’s discuss a few examples to find the z score on TI-84 plus ce

## Find the Z Score corresponding to the 1^{st} Quartile using TI-84

We know the 1^{st} Quartile represents the 25^{th} percentile in the normal distribution.

Let’s first draw the normal distribution curve for percentile = 0.25

The following steps will guide how to calculate the z score corresponding to the 1^{st} Quartile on TI-84 plus Calculator:

- Press “
**2nd**” and then press “**VARS**”.This will display the**“DISTR”**screen. - Select “
**invNorm**” i.e 3rd option, and then press “ENTER” to bring up the invNorm wizard screen. - Type 0.25,0,1
- Type a closing parenthesis “)” and then press ENTER.

The resultant z-score for the left tail is **-0.67**

**Conclusion: **The Z-score associated with the 1^{st} Quartile in the normal standard distribution is **-0.67**.

**Cool Tip:** How to find percentile from z score on the TI-84 calculator!

## Find Z-Scores for the top 20^{th} Percentile on TI-84

The top 20% of the normal distribution indicates that only 20% of the data lies on the right of the normal standard curve.

Let’s first draw the normal distribution curve for the top 20^{th} percentile.

The minimum percentile required left to the required z-score is 80% i.e. (100-20)%.

As we know, **invNorm **takes the probability of values less than the required z-score. So, we will check the 0.80 probability in order to calculate the top 20% of the distribution.

To find the z-score for the 80 percentile, we will follow the below steps:-

The following steps will guide you on how to calculate the Z-Scores for the top 20^{th} Percentile on TI-84 Calculator:

- Press “
**2nd**” and then press “**VARS**”.This will display the**“DISTR”**screen. - Select “
**invNorm**” i.e 3rd option, and then press “ENTER” to bring up the invNorm wizard screen. - Type 0.80,0,1
- Type a closing parenthesis “)” and then press ENTER.

The resultant z-score is **0.8416**.

**Conclusion: **The Z-score associated with the top 20th Percentile in the normal standard distribution is **0.8416**.

**Cool Tip:** How to Calculate Z Score in Excel!

## Conclusion

I hope the article on how to find the z score on **TI-84 plus calculator** is useful to you.

**invNorm** (Inverse normal distribution) function is used to calculate the z score from the percentile on the TI-84 calculator.

You can find more topics about Z-Score and how to calculate z score given the area on the ZScoreGeek home page.