Tests for Interval and Ratio Data

Question 1

The ____________________ and the ____________________ are the most commonly used inferential statistical tests for variables measured on an interval or ratio scale.

Answer 1

• Student’s T-test
• ANOVA

Question 2

The _____________________ is used to evaluate hypotheses about the differences between two means.

Answer 2

Student’s T-test.

Question 3

The ANOVA is preferred when more than two means are to be compared, in order to reduce the _________________________.

Answer 3

Experimentwise error rate.

Question 4

The ______________________ is used when a study includes only one group and the group (sample) mean will be compared to a known population mean.

• Use:
  
  • One IV: Single group
  • One DV: Interval or ratio data
• Statistic: t
• df: (N - 1), where N = number of subjects.

Answer 4

Student’s t-Test for a Single Sample.

Question 5

The ___________________________ is the appropriate statistical test when a study includes two independent groups and the means of the two groups will be compared.

• Use:
  
  • One IV: 2 independent groups
  • One DV: Interval or ratio data
• Statistic: t
• df: (N - 2), where N = total number of subjects

Answer 5

Student’s t-Test for Independent Samples.

Question 6

The _______________________________ is used when the two means to be compared have come from correlated groups (e.g., a within-subjects design in which a single group of subjects will be compared to itself before and after the IV has been applied). Also appropriate when subjects have been matched on an extraneous variable and members of each matched pair have been assigned to a different group.

• Use:
  
  • One IV: 2 correlated groups
  • One DV: Interval or ratio data
• Statistic: t
• df: (N - 1), where N = number of pairs of scores

Answer 6

Student’s t-Test for Correlated Samples.

Question 7

The _________________ is used when a study includes one IV and 2+ independent groups, and one DV that is measured on an interval or ratio scale.

• Use:
  
  • One IV: 2+ independent groups
  • One DV: Interval or ratio data
• Statistic: F
• df: (C - 1)(N - C), where C = number of levels of the IV and N = number of subjects

Answer 7

ANOVA.

Question 8

As opposed to the t-test, the ANOVA enables a researcher to evaluate the relative contributions of different factors to the total amount of variability observed in a set of scores. This is done by “partitioning the ________________.”

Answer 8

Sum of Squares.

Question 9

The one-way ANOVA divides the ___________ sum of squares (SST) into a ______________ sum of squares (SSB) and a _________________ sum of squares (SSW).

Answer 9

• Total
• Between-groups
• Within-group

SST = SSB + SSW

Question 10

In an ANOVA, the sums of squares are converted to mean squares (variances) by dividing each sum of squares by the appropriate degrees of freedom (for the ANOVA, the df are used not only to identify the _________________, but to calculate the ___________).

Answer 10

• Critical value
• F-ratio

Question 11

• Mean Square Total =
• Mean Square Between =
• Mean Square Within =

Answer 11

• MST = SST/df
• MSB = SSB/df
• MSW = SSW/df

Question 12

______________ is a pooled measure of variability within each of the treatment groups, and is an estimate of variability due only to error; ____________ is a measure of variability between treatment groups, estimating the variability due to both error and the effects of the IV.

Answer 12

• MSW
• MSB

Question 13

The F-ratio is calculated by dividing __________ by ___________.

Answer 13

F = MSB/MSW = (treatment + error)/error.

Question 14

In an ANOVA, when H₀ is true, MSB and MSW are _______________ and F = ___.

Answer 14

• The same
• 1

Question 15

When the H₀ is false, MSB is ___________ than MSW and F is ___ 1.

Answer 15

• Greater
• >

Question 16

If a study includes more tha two groups, a statistically significant F indicates that there is some difference between the groups, but does not indicate which groups differ. ______________ tests are usually conduceted to ID which group means are significantly different.

• The _______________ can be used to make all pairwise and complex comparisons (Group 1 vs. Group 2; Group 1 vs. Groups 2 and 3, etc.)
• The _______________ to make pairwise comparisons when groups are of equal size

Answer 16

• Post-hoc
• Scheffe S test
• Tukey test

Question 17

The ___________________ is an extension of the one-way ANOVA and is used when a study includes 2+ IVs. F-ratios are obtained for the main effects of each IV and their interactions.

• Use:
  
  • 2+ IVs; Independent groups
  • 1 DV; Interval or ratio data
• Statistic: F

Answer 17

Factorial Analysis of Variance.

Question 18

The ________________________ is a type of factorial ANOVA that is employed when “blocking” has been used to control an extraneous variable. It involves treating the extraneous variable as an IV so that its main and interaction effects can be statistically analyzed. It also increases statistical power by reducing within-group variability.

Answer 18

Randomized Block ANOVA.

Question 19

The ___________________ combines the ANOVA with regression analysis and allows an investigator to control an extraneous variable by statistically removing the portion of variability in the DV that is due to the extraneous variable. This reduces within-group variability, resulting in a more powerful test. It requires using subjects’ scores on the extraneous variable (the “covariate”) to adjust their scores on the DV.

Answer 19

Analysis of Covariance (ANCOVA).

Question 20

The _____________________ is appropriate for studies using a within-subjects design in which the different levels of the IV or combinations of the levels of two or more IVs are sequentially administered to each subject.

Answer 20

Repeated Measures ANOVA.

Question 21

The ___________________ is the appropriate test for studies using a mixed design in which at least one IV is a between-groups variable and one IV is a within-subjects variable.

Answer 21

Mixed (Split-Plot) ANOVA.

Question 22

_____________________ is used when the study involves one or more quantitative IVs, and the researcher wants to evaluate the shape or form of the relationship between the IV and DV. The results indicate whether or not there is a statistically significant linear or nonlinear (quadratic, cubic, quartic) relationship between variables.

Answer 22

Trend Analysis.

Question 23

The __________________ can be used when a study inclues one or more IVs and 2+ DVs that are each measured on an interval or ratio scale. It allows an investigator to simultaneously assess the effects of the IVs on all of the DVs and thereby helps control the experimentwise error rate.

Answer 23

Multivariate Analysis of Variance (MANOVA).