A series of free Statistics Lectures with lessons, examples & solutions in videos.
This is page twenty of the series of free video lessons, “Statistics Lectures”. These lectures discuss various types of samples t-test, covering one sample z-test and one sample t-test.
A survey claims that 9 out of 10 doctors recommend aspirin for their patients with headaches. To test this claim, a random sample of 100 doctors is obtained. Of these 100 doctors, 82 indicate that they recommend aspirin. Is this claim correct? Use alpha = 0.05
z-Tests are commonly done when the population standard deviation is known. t-Tests are commonly done when the population standard deviation is unknown. We use the t-distribution because the unknown population standard deviation is now a value we must estimate.
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