S7Exam3Review

Why does the t distribution have greater variability in the tails of the distribution compared to a normal distribution?

• because the t distribution is positively skewed

• because the sample variance is substituted for the population variance to estimate the standard error in this distribution

• because the normal distribution is negatively skewed compared to the t distribution

• it does not; the t distribution is the same as a normal distribution

What are the degrees of freedom for a t distribution?

• none

• N

• n

• n-1

A researcher conducts a one-sample t test with a sample of 24 participants. What are the degrees of freedom for this hypothesis test?

• 23

• 22

• 24

• 25

A researcher conducts a one-sample t test. What are the critical values for a two-tailed hypothesis test at a .05 level of significance when df = 14?

• 1.761

• 1.771

• ±2.145

• ±2.160

A between-subjects design is one in which:

• the same participants are observed in each group

• different participants are observed in each group

• no participants are observed in any groups

• participants are subjected to a treatment

What types of samples are selected using the between-subjects design?

• dependent samples

• in-between samples

• independent samples

• related samples

Which of the following is a way to select independent samples?

• select one sample from the same population and randomly assign participants in the sample to groups

• select a sample from two populations

• select a sample from one population, then observe those same participants in each group

• both a and b

A researcher conducts a two-independent-sample t test with a sample of 24 participants, where 12 participants are observed in each group. What are the degrees of freedom for this hypothesis test?

• 22

• 23

• 24

• 25

A researcher conducts a two-independent-sample t test. What are the critical values for a two-tailed hypothesis test at a .05 level of significance when n = 14 participants in each group?

• ±2.179

• ±2.145

• ±2.048

• ±2.056

A researcher compares differences in personality traits among pairs of identical twins. What type of research design did the researcher use?

• repeated-measures design

• matched-pairs design