Question 1173386: Question 1:
A sample of 10 networking sites for a specific month has a mean of 26.1 and a standard deviation of 4.2. Find the 99% confidence interval of the true mean.
Question 2:
In a survey of 500 infants chosen at random, it is found that 240 are girls. Are boy and girl births equally likely according to this survey (use α = 0.05)
Question 9:
Is the choice of exercise equipment dependent upon gender? Recent records from a large gym indicated the following equipment usage. At the 0.05 level of significance, is there a relationship?
Treadmill Elliptical Bike
Male 120 60 75
Female 100 95 82
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! half-interval is t (0.995, df=9)*s/sqrt(n)
=3.25*4.2/sqrt(10)
=4.32
the 99% C( is (21.8, 30.4)
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Ho: girls=0.5
Ha: girls NE 0.5
alpha = 0.0=p(reject Ho|Ho true}
test stat z=(phat-p)/sqrt (p(1-p)/n)
critical value |z|>1.96
z=0.02/sqrt(0.25/500)
=0.89
fail to reject Ho. Insufficient evidence to reject the null hypothesis.
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The expected value are
105.45--74.3--75.25
114.55--80.7--81.75
Chi-Square is 9.14 which has a p-value of 0.01, and the evidence suggests a relationship, not independence.
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