Stats - Chapter 7

If the researcher fails to reject the null hypothesis when there really is a difference, this is an example of a

type II error (pg 211 of PDF)

Which hypothesis is stated in the null form?

There is no difference between the vocabulary scores of average- and high-ability students.

A measure of meaningfulness that expresses the difference between the experimental and control group in standard deviation units is the

effect size (pg 216 of PDF)

A researcher decides to use an alpha of .01 and a power of .80. To determine the needed sample size the researcher must ascertain the expected

effect size (pg 217 of PDF)

A null hypothesis is

statistical hypothesis that assumes that there is no difference among the effects of treatments (pg 211 of PDF)

If a researcher finds a small difference in average test scores between a large sample (over 700) of experimental participants and a large sample (same size) of control participants, it is very likely that the difference is

statistically significant but does not have a high degree of meaningfulness (pg 226 of PDF)

When a researcher states that a result is significant, this means that

the result is unlikely to be a chance occurence

When an experimenter states that the level of significance is the .05 level, he is setting the probability of committing which type of error?

type I error ( pg 211 of PDF)

When a researcher claims that there is a difference between treatments (i.e., rejects the null hypothesis) when there really is no difference, what type of error is this?

type I error (pg 212 of PDF)