Find the p value from a z value

You can easily find the p value from a z value with our . If you want to find the p value by using a table with standard normal probabilities, instructions are given below.

Finding the $p$ value from a $z$ value, using the table with standard normal probabilities

Assuming a table for both negative and positive $z$ values, showing lower tail probabilities

Two sided	$p$ value is the probability of finding the observed $z$ value or a more extreme value, given that the null hypothesis is true. If you have found a positive $z$ value ($z \geq 0$): Find the row corresponding to the $z$ value you found up to the first decimal, and the column corresponding to the second decimal. At the intersection point of this row and column, you find the left sided $p$ value $p_{left}$ The two sided $p$ value is $2 \times (1 - p_{left})$ If you have found a negative $z$ value ($z < 0$): Find the row corresponding to the $z$ value you found up to the first decimal, and the column corresponding to the second decimal. At the intersection point of this row and column, you find the left sided $p$ value $p_{left}$ The two sided $p$ value is $2 \times p_{left}$
Right sided	$p$ value is the probability of finding the observed $z$ value or a larger value, given that the null hypothesis is true. Find the row corresponding to the $z$ value you found up to the first decimal, and the column corresponding to the second decimal. At the intersection point of this row and column, you find the left sided $p$ value $p_{left}$ The right sided $p$ value is $1 - p_{left}$ Note that if you decided in advance to test right sided but you find a negative $z$ value, you still compute the right sided $p$ value $1 - p_{left}$, resulting in a $p$ value larger than 0.5.
Left sided	$p$ value is the probability of finding the observed $z$ value or a smaller value, given that the null hypothesis is true. Find the row corresponding to the $z$ value you found up to the first decimal, and the column corresponding to the second decimal. At the intersection point of this row and column, you find the left sided $p$ value Note that if you decided in advance to test left sided but you find a positive $z$ value, you still compute the left sided $p$ value, resulting in a $p$ value larger than 0.5.

Finding the $p$ value from a $z$ value, using the table with standard normal probabilities

$p$ value is the probability of finding the observed $z$ value or a more extreme value, given that the null hypothesis is true.

$p$ value is the probability of finding the observed $z$ value or a larger value, given that the null hypothesis is true.

$p$ value is the probability of finding the observed $z$ value or a smaller value, given that the null hypothesis is true.