Question 126321: The following data is a random sample of 1st quiz scores from previous classes.
9.5, 6.5, 4.25, 8.5, 7.5, 4.5, 4.25, 6, 7
x=6.44 s = 1.89
A) Based on the above data, find a 95% confidence interval for the average score on the 1st quiz.
B) Describe what the confidence interval tells you
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! The following data is a random sample of 1st quiz scores from previous classes.
9.5, 6.5, 4.25, 8.5, 7.5, 4.5, 4.25, 6, 7
x-bar=6.44 s = 1.89
A) Based on the above data, find a 95% confidence interval for the average score on the 1st quiz.
t-value for a two-tailed test with alpha = 5% and 8 degrees of freedom = 2.306
E = t*(s/sqrt(n))
E = 2.306*(6.44/sqrt(9))
E = 1.074224
95% Confidence Interval: (6.44-1.074224,6.44+1.074224) = (5.3657765 ,7.514224)
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B) Describe what the confidence interval tells you
We are 95% confident that the population mean associated with the
sample data is between those two numbers.
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Cheers,
Stan H.
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