Question 1170052: You are performing a two-tailed test with test statistic z = 2.75, find the p-value to 4 decimal places. Answer by Theo(13342) (Show Source):
the p-value to the right of the z-score is 1 minus that = .0029798186.
round to 4 decimal places, and .....
the p-value to the left is .9970 and the p-value to the right is .0030.
i used the ti-84 plus to get these values.
if you use an online calculator like the one found at , it will tell you .....
that the area to the left of the z-score = 0.99702 which can be rounded to 4 decimal places to = .9970.
that the area to the right of the z-score = 0.0029798 which can be rounded to 4 decimal places to = .0030.
it depends on the critical z-score / critical alpha of your study to determine if the results are significant or not.
at 90% two tailed confidence level, the alpha on each end is .05 and the critical z-score is plus or minus plus or minus 1.65.
the results will be significant at the 90% confidence level.
at 95% two tailed confidence level, the alpha on each end is .025 and the critical z-score is plus or minus 1.96.
the results will be significant at the 95% confidence level.
at 99% two tailed confidence level, the alpha on each end is .005 and the critical z-score is plus or minus plus or minus 2.576.
the results will be significant at the 99% confidence level.
99% confidence level is usually about high as they go.
a z-score of 2.75 and a p-value of .003 exceed those limits.
2.75 is greater than 2.576 and .003 is less than .005.
if it exceed the limits at 99% confidence level, it will exceed the limits of any confidence level below that.
here are the results of the analysis using the z-score referenced above.
