Question 1096633:  It has been reported that the average credit card debt for college seniors at the college book 
store for a specific college is $3262 and the standard deviation is $1100. The student senate at 
a large university feels that their seniors have debt much less than this, so it conducts a study of 
50 randomly selected seniors and finds that average debt is $2995. Is the student senate correct 
with   0.05. 
 Answer by Boreal(15235)      (Show Source): 
You can  put this solution on YOUR website! Assuming a z test here with known sd. 
the 95% CI, if this is used will be mean +/- 1.96*1100*sigma/sqrt(n) 
this is +/- $304/90 or $305 
The 95% CI is ($2690, $3300).  Because $3262 is in the confidence interval, one cannot conclude that this is statistically significant at the 0.05 level 
The z-test would be (2995-3262)/1100/sqrt(50)=-1.72 
With Ho being that there is no difference 
Ha being there is a difference 
alpha being 0.05  
test statistic of z=(bar-mean)/sigma/sqrt(n) 
critical value is |z|>1.96 
p-value is 0.086, which is greater than 0.05 so Ho is not rejected. 
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