Question 1003689: Hello Tutor,
I am trying to figure it out this problem. not sure what I missed.
Thank you in advance.
Q.You were interested in how long the average psychology major at your college studies per night, so you asked 10 psychology majors to tell you the amount they study. They told you the following times: 2, 1.5, 3, 2, 3.5, 1, 0.5, 3, 2, 4.
(a) Find the 95% confidence interval on the population mean.
I got mean = 2.25 standard deviation = 1.05
standard error of the mean =1.05/square root of 10 = 0.332
95%= 1.96
2.25 + (1.962)(0.332) =2.90072
2.25- (1.962) (0.332) = 1.59928
but the answer is (1.45,3.05)
I am not sure what I am missing. please help. Thank you in advance.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! You were interested in how long the average psychology major at your college studies per night, so you asked 10 psychology majors to tell you the amount they study. They told you the following times: 2, 1.5, 3, 2, 3.5, 1, 0.5, 3, 2, 4.
(a) Find the 95% confidence interval on the population mean.
I got mean = 2.25 standard deviation = 1.05
You treated the data as a population and found the population standard deviation.
Treating the data as a sample the standard deviation is 1.112
Then::
standard error of the mean = 1.112/square root of 10 = 0.352
95%= 1.96
2.25 + (1.962)(0.352) =2.9399
2.25- (1.962) (0.352) = 1.560
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Comment:: Your work looks good to me.
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Cheers,
Stan H.
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