SOLUTION: two groups of patients were given. eight in each group. the mean and standard deviation of both groups given. carry out a formal test of hypothesis that the population means ar

Question 260070: two groups of patients were given. eight in each group. the mean and standard deviation of both groups given.
carry out a formal test of hypothesis that the population means are the same. what assumptions are required for this test.
obtain a 95% confidence interval for the difference between population means
plz tell how to do this
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
patients undergoing bypass surgery were randomised into one of the two groups.
Group 1 - received a 50% nitrous oxide and 50% oxygen mixture continously for 24 hrs
Group 2 - received a 50 % notrous oxide and 50% oxygen only during the operation
table shows red cell folate levels for grous 24 hrs later
group 1 group 2
243 206
251 210
275 226
291 249
347 255
354 273
380 285
392 295

mean 316.6 249.9
SD 58.7 33.6

carry out a formal test of hypothesis that the population means are the same. what assumptions are required for the test
Ho: u1-u2 = 0
Ha: u1-u2 is not 0
-------------------------
I ran a 2-Sample Ttest on a TI calculator and got the following:
test statistic: t = 2.78928...
p-value = 2*P(t > 2.78928,df = n1+n2-2 = 14) = 0.01742
(The calculator came up with df = 11.14234...)
Conclusion: Based on the p-value, reject Ho at the 1% significance level,
or fail to reject Ho at the 5% significance level.
==============================================================================
obtain a 95% confidence interval for the difference between the population means
I ran a 2-Sample TInterval and got the following:
14.15 < u1-u2 < 119.25
These results based on:
sample mean difference: 316.6-249.9 = 66.7
sample standard error = (1/2)(119.25-14.15) = 52.66
=======================================================
Cheers,
Stan H.
discuss the relationship between the two above.

Cheers,
Stan H.
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