χ²* = 3.841

Right-tail α = 0.05, 1 degree of freedom.

Critical values of chi-square. Column headings are the area to the right of the critical value.
df0.9950.990.9750.950.90.10.050.0250.010.005
10.0000390.0001570.0009820.00390.01582.7063.8415.0246.6357.879
20.01000.02010.05060.1030.2114.6055.9917.3789.21010.597
30.07170.1150.2160.3520.5846.2517.8159.34811.34512.838
40.2070.2970.4840.7111.0647.7799.48811.14313.27714.860
50.4120.5540.8311.1451.6109.23611.07012.83315.08616.750
60.6760.8721.2371.6352.20410.64512.59214.44916.81218.548
70.9891.2391.6902.1672.83312.01714.06716.01318.47520.278
81.3441.6462.1802.7333.49013.36215.50717.53520.09021.955
91.7352.0882.7003.3254.16814.68416.91919.02321.66623.589
102.1562.5583.2473.9404.86515.98718.30720.48323.20925.188
112.6033.0533.8164.5755.57817.27519.67521.92024.72526.757
123.0743.5714.4045.2266.30418.54921.02623.33726.21728.300
133.5654.1075.0095.8927.04219.81222.36224.73627.68829.819
144.0754.6605.6296.5717.79021.06423.68526.11929.14131.319
154.6015.2296.2627.2618.54722.30724.99627.48830.57832.801
165.1425.8126.9087.9629.31223.54226.29628.84532.00034.267
175.6976.4087.5648.67210.08524.76927.58730.19133.40935.718
186.2657.0158.2319.39010.86525.98928.86931.52634.80537.156
196.8447.6338.90710.11711.65127.20430.14432.85236.19138.582
207.4348.2609.59110.85112.44328.41231.41034.17037.56639.997
218.0348.89710.28311.59113.24029.61532.67135.47938.93241.401
228.6439.54210.98212.33814.04130.81333.92436.78140.28942.796
239.26010.19611.68913.09114.84832.00735.17238.07641.63844.181
249.88610.85612.40113.84815.65933.19636.41539.36442.98045.559
2510.52011.52413.12014.61116.47334.38237.65240.64644.31446.928
2611.16012.19813.84415.37917.29235.56338.88541.92345.64248.290
2711.80812.87914.57316.15118.11436.74140.11343.19546.96349.645
2812.46113.56515.30816.92818.93937.91641.33744.46148.27850.993
2913.12114.25616.04717.70819.76839.08742.55745.72249.58852.336
3013.78714.95316.79118.49320.59940.25643.77346.97950.89253.672
4020.70722.16424.43326.50929.05151.80555.75859.34263.69166.766
5027.99129.70732.35734.76437.68963.16767.50571.42076.15479.490
6035.53437.48540.48243.18846.45974.39779.08283.29888.37991.952
7043.27545.44248.75851.73955.32985.52790.53195.023100.425104.215
8051.17253.54057.15360.39164.27896.578101.879106.629112.329116.321
9059.19661.75465.64769.12673.291107.565113.145118.136124.116128.299
10067.32870.06574.22277.92982.358118.498124.342129.561135.807140.169

Every value is calculated in your browser from the standard normal distribution (Marsaglia’s series for Φ) and rounded to four decimals; the tables were checked cell by cell against an independent calculation. These tables give the area to the left of z. Some textbooks, including the NIST handbook, print the area from 0 to z instead, which is the left area minus 0.5 for positive z.

How to read the chi-square table

Find the row for your degrees of freedom and the column for your significance level, which is the area to the right of the critical value. With 1 degree of freedom at α = 0.05 the critical value is 3.841; with 10 degrees of freedom it is 18.307. If your statistic is larger than the critical value, reject the null hypothesis.

Common questions

Is the chi-square test one-tailed?

Goodness-of-fit and independence tests use the right tail, because large differences between observed and expected counts make the statistic large.

Why are the left columns (0.995 to 0.90) so small?

Those columns leave most of the area to the right. They are used for left-tail tests and for confidence intervals for a variance.

The studio notebook

A useful place to begin.

Clear steps, considered details, and ideas you can put to use.