A negative Z score value indicates the raw score value is either left or below the mean of the standard normal distribution.

The negative z score in the z-table represents the area under the bell curve to the left of z.

If the z score value is negative, use the negative z table to find an area on the left of the mean of the distribution.

You can refer Z score calculator article which explains how to calculate the Z score using the z score formula below.

z = (x -μ )/σ

Where:

  • μ = is the population mean for the unstandardized value
  • σ = is the population standard deviation for the unstandardized value
  • x = is the raw score value
  • z = is the calculated z-score value.

In this tutorial, we will discuss negative z score, and how to read a negative z score chart with examples.

Negative Z-Score Table

A negative z-score value is either left or below the mean of standard normal distribution.

A negative z-score table has values less than 0.

Negative Z Score Chart

z 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0.0
-3.4 0.0002 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003
-3.3 0.0003 0.0004 0.0004 0.0004 0.0004 0.0004 0.0004 0.0005 0.0005 0.0005
-3.2 0.0005 0.0005 0.0005 0.0006 0.0006 0.0006 0.0006 0.0006 0.0007 0.0007
-3.1 0.0007 0.0007 0.0008 0.0008 0.0008 0.0008 0.0009 0.0009 0.0009 0.0010
-3.0 0.0010 0.0010 0.0011 0.0011 0.0011 0.0012 0.0012 0.0013 0.0013 0.0013
-2.9 0.0014 0.0014 0.0015 0.0015 0.0016 0.0016 0.0017 0.0018 0.0018 0.0019
-2.8 0.0019 0.0020 0.0021 0.0021 0.0022 0.0023 0.0023 0.0024 0.0025 0.0026
-2.7 0.0026 0.0027 0.0028 0.0029 0.0030 0.0031 0.0032 0.0033 0.0034 0.0035
-2.6 0.0036 0.0037 0.0038 0.0039 0.0040 0.0041 0.0043 0.0044 0.0045 0.0047
-2.5 0.0048 0.0049 0.0051 0.0052 0.0054 0.0055 0.0057 0.0059 0.0060 0.0062
-2.4 0.0064 0.0066 0.0068 0.0069 0.0071 0.0073 0.0075 0.0078 0.0080 0.0082
-2.3 0.0084 0.0087 0.0089 0.0091 0.0094 0.0096 0.0099 0.0102 0.0104 0.0107
-2.2 0.0110 0.0113 0.0116 0.0119 0.0122 0.0125 0.0129 0.0132 0.0136 0.0139
-2.1 0.0143 0.0146 0.0150 0.0154 0.0158 0.0162 0.0166 0.0170 0.0174 0.0179
-2.0 0.0183 0.0188 0.0192 0.0197 0.0202 0.0207 0.0212 0.0217 0.0222 0.0228
-1.9 0.0233 0.0239 0.0244 0.0250 0.0256 0.0262 0.0268 0.0274 0.0281 0.0287
-1.8 0.0294 0.0301 0.0307 0.0314 0.0322 0.0329 0.0336 0.0344 0.0351 0.0359
-1.7 0.0367 0.0375 0.0384 0.0392 0.0401 0.0409 0.0418 0.0427 0.0436 0.0446
-1.6 0.0455 0.0465 0.0475 0.0485 0.0495 0.0505 0.0516 0.0526 0.0537 0.0548
-1.5 0.0559 0.0571 0.0582 0.0594 0.0606 0.0618 0.0630 0.0643 0.0655 0.0668
-1.4 0.0681 0.0694 0.0708 0.0721 0.0735 0.0749 0.0764 0.0778 0.0793 0.0808
-1.3 0.0823 0.0838 0.0853 0.0869 0.0885 0.0901 0.0918 0.0934 0.0951 0.0968
-1.2 0.0985 0.1003 0.1020 0.1038 0.1056 0.1075 0.1093 0.1112 0.1131 0.1151
-1.1 0.1170 0.1190 0.1210 0.1230 0.1251 0.1271 0.1292 0.1314 0.1335 0.1357
-1.0 0.1379 0.1401 0.1423 0.1446 0.1469 0.1492 0.1515 0.1539 0.1562 0.1587
-0.9 0.1611 0.1635 0.1660 0.1685 0.1711 0.1736 0.1762 0.1788 0.1814 0.1841
-0.8 0.1867 0.1894 0.1922 0.1949 0.1977 0.2005 0.2033 0.2061 0.2090 0.2119
-0.7 0.2148 0.2177 0.2206 0.2236 0.2266 0.2296 0.2327 0.2358 0.2389 0.2420
-0.6 0.2451 0.2483 0.2514 0.2546 0.2578 0.2611 0.2643 0.2676 0.2709 0.2743
-0.5 0.2776 0.2810 0.2843 0.2877 0.2912 0.2946 0.2981 0.3015 0.3050 0.3085
-0.4 0.3121 0.3156 0.3192 0.3228 0.3264 0.3300 0.3336 0.3372 0.3409 0.3446
-0.3 0.3483 0.3520 0.3557 0.3594 0.3632 0.3669 0.3707 0.3745 0.3783 0.3821
-0.2 0.3829 0.3897 0.3936 0.3974 0.4013 0.4052 0.4090 0.4129 0.4168 0.4207
-0.1 0.4247 0.4286 0.4325 0.4364 0.4404 0.4443 0.4483 0.4522 0.4562 0.4602
-0.0 0.4641 0.4681 0.4721 0.4761 0.4801 0.4840 0.4880 0.4920 0.4960 0.5000

Negative Standard Normal Distribution Table

This negative z score table having a z value between 0 to -3.4 represents the area under the bell curve to the left of z.

How to Find Negative Z Score on Z Table?

To understand how to use a negative z-score chart, let’s take an example.

Find the z-score based on the below information

  • Mean: 71
  • Standard deviation: 4
  • Raw score: 68

To find the z-score, use below z-score formula.

z = (x – μ )/σ

Where,

  • x = raw score
  • μ = mean of the data set
  • σ = standard deviation of the data set.

Use the input parameters in the z-score formula

z = (68-71)/4

z = -0.75

Z-Score for a raw score of 68 is -0.75. This means that the raw score of 68 is a 0.75 standard deviation below the mean of 71.

The Z-score value is negative, hence use the negative z-score table to find the area.

Negative z-score chart

Using the above negative standard normal distribution table, the area for a negative z-score value of -0.75 is 0.2266 as marked in yellow color.

The corresponding area for z-score -0.75 is 0.2266 which is 22.66%

Conclusion

I hope the above article on how to use a negative z-score table with an example is helpful to you.