University of Ottawa PSY 2106 Exam Questions and Answers, Exams of Science education

University of Ottawa PSY 2106 Exam Questions and Answers, Exams of
Science education




Problem: we don't usually know the population SD which is needed to
calculate the Om (so no z-score) - ANSWERANSWER: estimate the population
o using the sample s (changing from a z-test to a t-test)



T-test - ANSWERt = M - mew

-----------

SM



T-test is used to compare the mean of a sample with a population when -
ANSWERthe population mean is known but the population standard
deviation is unknown



The sample variance will generally - ANSWERunderestimate its population
(biased estimate)

, Estimate the population variance from the - ANSWERsample scores



S^2 = - ANSWERSS

----

n-1



Once the s is calculated - ANSWERwe are able to calculate the standard error
of the distribution means



SM = - ANSWERs / square root of n



T distributions have more - ANSWERvariability



The larger the value of df (n-1) - ANSWERthe more closely the t distribution
approximates z, a normal distribution



As the sample size increases - ANSWERit better approximates its population,
so the estimate is more accurate



Numerator (M - mew) - ANSWERthe difference between the sample M and
the population mew



Denominator (SM) - ANSWERthe expected difference due to chance or SM



When difference in the numerator >SM in the denominator - ANSWERthe t-
statistic will >1