difference between the average

Question

On the "Television watching" tab of the spreadsheet, a column titled "Sample of U.K. residents" lists the hours each of 15 randomly selected United Kingdom residents reported spending watching television during the past week. A second column, titled "Average for Americans," has been filled entirely with "28" figures to represent the average number of hours Americans spend watching television. Using the appropriate statistical procedure, determine whether the average time spent watching television among the 15 U.K. residents is significantly different from 28, the average for Americans. Based on the results of your analysis, which figure represents the probability that the difference between the average amount of television time among the 15 U.K. residents (22.4 hours) and the 28-hour norm among Americans could have appeared due to a random process?

Answer 1

https://onlinecourses.science.psu.edu/stat500/node/50

 

The difference of the sample means will suffice.

 

The standard deviation you will need for your hypothesis test is:

 

 

S = square root of ( S1^2/N1 + S2^2/N2) 

where S1 and S2 are the standard deviations of the samples, and

N1=15 and N2=28 are the respective sample sizes.

 

Divide the difference between the sample means by this standard deviation S to get

your t statistic.

 

Now for the degrees of freedom:

 

 df = (N1-1)*(N2-1)/ (N2-1)*C^2 + (N1-1)*(C^2-1)

 

  where C = (S1^2/N1)/(S1^2/N1 + S2^2/N2)

 

You can now use your t-table

 

https://onlinecourses.science.psu.edu/stat500/node/50