SYMBOLS Symbol | Stands For |
|  (0.0K) | standard error of the mean |  (0.0K) | mean of the sampling distribution of means, which equals µ |  (0.0K) | z score for the sampling distribution of means |  (0.0K) | estimated standard error of the mean |  (0.0K) or t | t score, which is an estimate of a z score | CI | confidence interval | df | degrees of freedom | t.05 or t.01 | t scores from Table B cutting off deviant 5% or 1% of the distribution [occur with probability of .05(.01) or less] | H0 | null hypothesis | a | alpha level, the level at which we test H0 | H1 | alternative hypothesis | m0 | specific value representing the "untreated" population mean | tcomp | computed t score | tcrit | critical t score from Table B | Type I, or a, error | rejecting true H0 | Type II, or b, error | failing to reject false H0 |
FORMULAS Formula 9-4. Equation for estimated standard error of the mean  (1.0K) The estimated standard error is found by dividing the sample standard deviation by the square root of
sample size. Formula 9-5. Equation for  (0.0K) , which is an estimate of  (0.0K)  (1.0K) This equation is used to test hypotheses about the value of m. It is the formula for the one-sample t test. Formulas 9-6 and 9-7. Equations for 95% and 99% confidence intervals  (2.0K) t.05 and t.01 are the t scores cutting off the deviant 5% and 1% of the distribution of t, respectively. The values of t are found in Table B with df = N – 1. |