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ATH241 23 In a sam standard deviation of 39.2. a.) What is the best point estimate of the mean number of hours it takes stude
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Answer #1

a)

best point estimate=71.8

b)

degree of freedom=   DF=n-1= 42-1 = 41

c)

Level of Significance ,    α =    0.07
't value='   tα/2=   1.86    [Excel formula =t.inv(α/2,df) ]

d)

sample std dev ,    s =    39.2
Sample Size ,   n =    42
Sample Mean,    x̅ =   71.8

Standard Error , SE =   s/√n =   6.0487
margin of error ,   E=t*SE =   11.253


confidence interval is       
Interval Lower Limit=   x̅ - E =    60.547
Interval Upper Limit=   x̅ + E =    83.053

   So, confidence interval is (   60.547   < µ <    83.053   )

e)

margin of error ,   E=t*SE = 1.8605*6.0487 = 11.253

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