Statistics 5 Probability and Z-Scores

Hypothesis Testing Using Z-Scores

3.Significance level – setting the a

na - our choice of probability (p) value – (.05 - .01 - .001 - etc.)

n.05 = 5 (out of 100) chances of being different

n.p < a - reject H0, accept H1 (this is statistically significant)

n.p > a - accept H0, reject H1 (this is NOT statistically significant)

4.Rejection Region

nreject H0 = sample x is significantly different than m

nCritical values – calculated test values

nz-scores (must know m and σ)

nt-scores (when m and σ are not known – more common method)

nIf sample z-scores in tail – reject the H0 (you found sig. diff)

nif sample z-scores in body – accept the H0 (you found NO sig.)