Thompson Rivers University

PSYC 2101

Queston 1:
a. The z-score is the exact locaton of each X value within a distributon. The z-score is important
because it describes how much the individual score differs from the average (using the standard
deviaton). The z-score also tells exactly where the original score is located in the distributon.
b. Characteristcs of the normal distributon curve are that it is symmetrical with the highest
distributon in the middle, and the frequencies taper off as you move toward either extreme.
Probability is equivalent to proporton, and due to the fact that a distributon curve is
symmetrical, each side shows an equal proporton.
c. The central limit theorem describes that the average of the sample means will be the
populaton mean, and that the standard deviaton of the sample means will equal the standard
error of the populaton mean. The standard error of the mean gives accuracy of the sample
mean by measuring the variability of the sample means.
d. Null hypothesis is important to determine whether or not the test is supported, by separatng
the equaton from the experimenters values. It will generally state the opposite of the
experimenters predicton (saying that the treatment has no effect).
e. A type 1 error is a “false positve”, which occurs when a researcher rejects a true null
hypothesis incorrectly.