Question 1157289: In study , researchers wanted to measure the effect of alcohol on the hippocampal region , the portion of the brain responsible for long - term memory storage , in adolescents The researchers randomly selected 21 adolescents with alcohol use disorders to determine whether the hippocampal volumes in the alcoholic adolescents were less than the normal volume of 9.02 cm An analysis of the sample data revealed that the hippocampal volume is approximately normal with no outliers and = 8.14 cm and s 0.7 cm Conduct the appropriate test at the = level of significance . the null and alternative hypotheses . Please include null hypothesis, t-stats, P value, and conclusion of hypothesis
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! units should be cm^3 since volume
Ho: Volume greater than or equal to normal mu1>=mu2
Ha: volume less than normal, mu1 less than mu 2
alpha =0.05 p{reject Ho|Ho true}
test statistic is a t0.95, df=20)
critical value t<-1.725
calculations t=(xbar-mean)/s/sqrt(n)
=(8.14-9.02)/0.7/sqrt(21)
=-0.88*sqrt(21)/0.7
=-5.76
strongly reject Ho and conclude the hippocampal volume in alcoholic adolescents is less than normal ones.
p<5.8 x 10^-6 (generally <0.0001 is sufficient
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