EPIB301 Exam 2 Questions with Correct
Answers
what is the central limit theorem?
as the sample size increases, the sampling distribution of the sample mean becomes more normal
and closer to the population distribution
alternative hypothesis
the hypothesis that the researcher is trying to find support for and that prior studies don't show
evidence for
null hypotheis
the hypothesis that represents no change from prior knowledge
what are hypotheses?
claims about plausible values of one or more unknown population parameters
can we prove an alternative hypothesis?
No, we can only say that is strong support for the null or alternative hypothesis (reject/fail to
reject null) since the sample size is limited
what is alpha? or type I error?
the probability of rejecting the null hypothesis given it is true (saying there is a change when
there isn't)
what does it mean to set a type I error rate before hypothesis testing?
, setting the maximum allowable probability of making a Type I error
why do we need to set our type I error rate before hypothesis testing?
alpha is used for a hypothesis testing decision and the results of the test cannot be what we use to
dictate the alpha necessary for make a testing decision
why are lower alphas better?
better for real-life application; saying that there's a lower chance of making a mistake
what is beta? or type II error?
the probability of failing to reject the null given the null hypothesis is false (saying there isn't a
change when there is one)
what is the power of a test?
the probability of rejecting the null hypothesis given the null hypothesis is false (1-beta; saying
there is a change when there really is one)
What do we need to assume in order to compute the test statistic?
that the null hypothesis is true
what are test statistics?
standardized values of sample statistics that we compare to a normal distribution (taking an
observed sample mean and Z-scoring it to convert to standard normal)
what does a higher Z-Score indicate for a two sided alternative hypothesis? or a right tailed
alt?
Answers
what is the central limit theorem?
as the sample size increases, the sampling distribution of the sample mean becomes more normal
and closer to the population distribution
alternative hypothesis
the hypothesis that the researcher is trying to find support for and that prior studies don't show
evidence for
null hypotheis
the hypothesis that represents no change from prior knowledge
what are hypotheses?
claims about plausible values of one or more unknown population parameters
can we prove an alternative hypothesis?
No, we can only say that is strong support for the null or alternative hypothesis (reject/fail to
reject null) since the sample size is limited
what is alpha? or type I error?
the probability of rejecting the null hypothesis given it is true (saying there is a change when
there isn't)
what does it mean to set a type I error rate before hypothesis testing?
, setting the maximum allowable probability of making a Type I error
why do we need to set our type I error rate before hypothesis testing?
alpha is used for a hypothesis testing decision and the results of the test cannot be what we use to
dictate the alpha necessary for make a testing decision
why are lower alphas better?
better for real-life application; saying that there's a lower chance of making a mistake
what is beta? or type II error?
the probability of failing to reject the null given the null hypothesis is false (saying there isn't a
change when there is one)
what is the power of a test?
the probability of rejecting the null hypothesis given the null hypothesis is false (1-beta; saying
there is a change when there really is one)
What do we need to assume in order to compute the test statistic?
that the null hypothesis is true
what are test statistics?
standardized values of sample statistics that we compare to a normal distribution (taking an
observed sample mean and Z-scoring it to convert to standard normal)
what does a higher Z-Score indicate for a two sided alternative hypothesis? or a right tailed
alt?
