P Value from Z Score Calculator

An online P value from Z score calculator is designed to determine the P value for a given hypothesis test corresponding to the calculated Z score and significant level.

Let us understand the phenomenon of Z score.

What is Z Score?

In the context of Statistics, a Z score or standard score actually gives you a proper idea about how much distance the point is located from the mean position. More technically, we can say that a Z score is the measure of how many standard deviations our raw data is above or below the average mean.

Z score Formula:

You can easily calculate the Z score by using the Z score equation as follows:

z = x – μ / σ

where;

x = Observed Value
μ = Mean Value
σ = Standard Deviation

The P value calculator from Z enables you to determine the P value from Z score.

Significance Level For Z Score:

Whenever you look forward to represent the critical value as Z score, you actually work for the Z score that has cumulative probability equal to that of the critical probability.

If our calculated Z score becomes less than or equal to the critical value of -1.645, then we can say that Z score is significant at 0.05. If our sample mean has a Z score that is actually greater or equal to a critical value of 1.645, then it is considered to be significant at 0.05 as well.

Z Score Table:

Everyone looks for better results from calculations they perform. A Z score table is specifically arranged so that you may get the exact p value against the calculated Z score. The complete Z score table is given as follows:

How To Find P Value From Z?

You can now find statistical P value from a given Z score with our best online P value from Z score calculator for free. Apart from this, you tend to calculate it manually sometimes when you want to understand each step involved in the calculations.

Let us solve some examples for you to understand how to calculate P value from Z.

Example # 01:

Suppose we performed a two-tailed hypothesis test and got a Z score of -1.25. How to find P value from Z?

Solution:

To find the P value, first we need to perform a proper analysis of Z score table to find -1.25.

So, the required P value is from table is 0.1056

Since we are performing a two tailed test, we will multiply this value by a factor of 2.

Required P value = 0.10565 * 2

P value = 0.2112

Apart from the manual calculations, you can also determine the P value using free Z score to P value calculator.

Example # 02:

You carried out a left tailed test. Calculate P value from Z when you are provided the following data:

Standard deviation = σ = 12
Statistical mean = μ = 30
Observed value = 10

Solution:

First of all, we have to determine the Z score by substituting the value in the Z score equation as follows:

z = x – μ / σ

z = 10 – 30 / 12

z = -1.66

Now we need to calculate P from Z score table as follows:

So, the required P value is from table is 0.0485.

Example # 03:

Just suppose that you are asked to perform a right tailed test for which you encountered with a Z score of 3.23. Calculate the P value from Z.

Solution:

We need to determine the P value by subjecting to the Z score chart:

P value from z score table is 0.9994

As we gave performed a right tailed test, we need to subtract this value from 1

Required p value = 1 – 0.9994

P value = 0.0006

How P Value From Z Score Calculator Works?

The P value calculator from Z involves only few basic steps that are quite easy to follow, it performs statistical calculations precisely, let’s find:

Input:

• First of all, select the type of p value from the drop down list
• Then put the value of z score and significant level
• Click ‘calculate’

Output:

On the basis of the type selected for P value, the calculator calculates either:

• Two-tailed P value
• Left-tailed P value
• Right-tailed P value
• Significant level for P value

FAQ’s:

What does P value 0.05 mean?

The P value 0.05 means that there exists a less than 5% chance of getting the results.

What if you get P value 0?

A zero p value means that your null hypothesis is considered to be true.

What is probability?

In statistics, probability tells us how likely an event is to occur.

What is meant by a Z test?

A type of statistical test that is use to calculate if two population means are different when variance is known and sample size is large enough.

Conclusion:

In statistics, a Z score tells us whether a score is typical for a set of data or not. P value has a strong demand in the field of engineering and data science where calculations are based on the predicted set of values. Making a use of P value from Z score calculator will tend to generate accurate P value for any hypothetical test under study.

References:

From the source of wikipedia: Z-test, Use in location testing, Standard score, Prediction intervals, Cluster analysis and multidimensional scaling, Standardizing in mathematical statistics.

From the source of khan academy: Calculating a P-value given a z statistic, z statistic

From the source of lumen learning: Z-Scores, The Empirical Rule