# Thread: calculating a test statistic

1. ## calculating a test statistic

Hi all I'm confused on calculating a test statistic. I am doing "hypothesis testing using t-scores" and my sample size is 100, sample mean 24.6, sample std. dev. 7.25. I have to decide if the population mean is significantly greater than 23 at the 0.05 level. If my df=100-1=99, do I use the df in my Student t chart with the infinity symbol? I guess I am confused because there is a df listing for 120, but not 100.

2. Originally Posted by peanutbutter
Hi all I'm confused on calculating a test statistic. I am doing "hypothesis testing using t-scores" and my sample size is 100, sample mean 24.6, sample std. dev. 7.25. I have to decide if the population mean is significantly greater than 23 at the 0.05 level. If my df=100-1=99, do I use the df in my Student t chart with the infinity symbol? I guess I am confused because there is a df listing for 120, but not 100.
You should use the listing for df = 120.

As you can see from the table at http://shazam.econ.ubc.ca/intro/critval.htmi it probably won't affect the conclusion you come to.