Psych 311 Exam 4
A researcher selects a sample of 110 participants and computes the following phi correlation coefficient: r = 0.31. What is the value of x^2? A) 3.84 B) 10.57 C) 34.10
10.57
A researcher selects a sample of 80 people and records the frequency of participants choosing a low, moderate, or high calorie dessert in a buffet. What are the degrees of freedom for this chi-square goodness-of-fit test? A) 2 B) 3 C) 79 D) 80
2
A researcher computes a 2 × 4 chi-square test for independence. What are the degrees of freedom for this test? A) 2 B) 3 C) 4 D) 8
3
A researcher compares the frequency of participants who sleep primarily on their stomach, back, or side during the night. What is the critical value for a chi-square goodness-of-fit test at a .05 level of significance? A) 2 B) 3 C) 3.84 D) 5.99
5.99
A researcher computes a 2 × 3 chi-square test for independence. What is the critical value for this test at a .05 level of significance? A) 3.84 B) 5.99 C) 7.81 D) 12.59
5.99
The correlation coefficient ranges from -1.0 to +1.0, with values closer to ±1.0 indicating
a stronger relationship between two factors
Select the description below that identifies the following correlation: r = .28, p < .01. A) the correlation is positive B) the correlation is statistically significant C) the coefficient of determination is .08 D) all of the above
all of the above
The formula for the chi-square test measures the size of the discrepancy between observed and _____________________frequencies.
expected
When the chi-square test for independence is significant, this indicates that there is significant variability between groups. (T/F)
false
When computing a chi-square goodness-of-fit test, the frequency expected in a given cell should never be less than
five
A chi-square goodness-of-fit test leads to a decision to retain the null hypothesis. Which of the following correctly explains this decision?
frequencies observed were statistically similar to the frequencies expected at each level of the categorical variable
The Kruskal-Wallis H test is used as a nonparametric alternative to which parametric test?
one way between subjects ANOVA
The Friedman test is used as a nonparametric alternative to which parametric test?
one way within subjects ANOVA
A researcher determines that x^2 = 3.76 to test for significance for a phi correlation coefficient. What was the decision for this phi correlation test?
retain null hypothesis
A chi-square goodness-of-fit test shows that the frequencies observed fit well with those that were expected. Hence, the decision was to
retain the null hypothesis
A researcher conducts a chi-square goodness-of-fit test in which k = 3 and x^2 = 4.32. What is the decision for this test at a .05 level of significance?
retain the null hypothesis
Suppose a correlation is computed in each of two samples. If the value of is the same in each sample, and is larger in Sample 1, then in which sample will the value of the correlation coefficient be larger?
sample 2
The degrees of freedom for a chi-square test for independence test are
(k1 - 1)(k2 - 1)
To compute the expected frequencies for a chi-square test for independence, we use which of the following formulas?
(row total x column total)/grand total
The correlation coefficient ranges between ____ and ____.
-1; +1
If r = .25, then the coefficient of determination is .= ___________06.
.06 (.0625 without rounding)
A 2 × 2 chi-square test for independence has ___ degrees of freedom.
1
A researcher measures the following correlation between number of years of education and life satisfaction: r = +0.08. What is the value of the coefficient of determination? A) 0.08 B) 0.16 C) 0.01 D) 0.11
0.01
A researcher measures the following correlation: r = -0.21. What is the value of the coefficient of determination? A) 0.04 B) -0.04 C) 0.42 D) -0.42
0.04
If x^2 = 5.32 and n = 40, then what is the value of the coefficient of determination? A) 0.133 B) 0.36 C) 0.64
0.133
A researcher computes a 4 × 6 chi-square test for independence with a sample of 120 participants, with x^2 = 14.79. What is the effect size for this result? A) 0.04 B) 0.20 C) 0.12 D) 0.35
0.20
A researcher measures the correlation between the frequency of self-esteem (high, low) and health status (lean/healthy, overweight/obese). Based on the frequencies for each nominal category given below, what is the value of the phi correlation coefficient? A) 0.08 B) 0.28 C) 0.52 D) 0.56
0.28
A researcher measures the relationship between two variables, X and Y. If = 340 and = 320,000, then what is the value of the correlation coefficient? A) 0.32 B) 0.34 C) 0.60 D) almost a zero correlation
0.60
A researcher measures the correlation between self-esteem (high, low) and physical fitness scores among school athletes. In the study, 12 participants reported high self-esteem and 12 reported low self-esteem. If Sy = 9.06 and My1-My2 = 11, then what is the value of the correlation coefficient? A) 0.61 B) 0.30 C) 0.39
0.61
A researcher measures the correlation in rankings for a sample of restaurants and consumers' rankings of their favorite restaurants. If SD^2= 96 and n = 12, then what is the value of the correlation coefficient? A) 0.07 B) 0.34 C) 0.66 D) 0.94
0.66
A researcher records the frequency of participants selecting one of four new slogans for an advertising campaign. If it was expected that among 200 people polled there would be no preference for any one slogan, then what was the expected frequency for each slogan.
50 people
What is a key distinction between parametric tests and nonparametric tests in terms of scales of measurement?
Parametric tests are used for interval and ratio data, whereas nonparametric tests are used for nominal and ordinal data.
One nonparametric statistical test is the chi-square test. Name three others.
Sign test Mann-Whitney U test Wilcoxen signe ranks T test Kruskal-Wallis H test Friedman test
Give the definition for a "third variable" or confound in correlational research.
Unanticipated variable not accounted for in the study that could be causing or correlating with observed changes in one or more other variables
Imagine you are a journal editor. A researcher reports means and standard deviations for groups for a study that required running a chi-square test. Is there a problem? What is the problem?
Yes, not meaningful to calculate means and SDs for chi-square data because the data represent frequency counts and they are measured on a nominal scale
An unanticipated variable not accounted for in a research study that could be causing or associated with observed changes in one or more measured variables is called
a confound variable
The normality assumption states that the population of X and Y scores form a bivariate ("two variable") normal distribution, such that A) the population of X and Y scores are normally distributed B) for each X score, the distribution of Y scores is normally distributed C) for each Y score, the distribution of X scores is normally distributed D) all of the above
all of the above
Which of the following is a limitation for interpreting a correlation? A) Correlations do not demonstrate cause-and-effect. B) Outliers can change the direction and/or strength of the correlation. C) Conclusions should not be drawn beyond the range of scores measured. D) all of the above
all of the above
Which of the following is an example of a parametric test? A) analysis of variance B) one-sample t-test C) Pearson correlation D) all of the above
all of the above
Which of the following is a statistical procedure used to test hypotheses about the discrepancy between the observed and expected frequencies in two or more nominal categories? A) one-way ANOVA B) analysis of regression C) chi-square test D) all of the above
chi squared test
Which of the following is an example of a nonparametric test? A) analysis of variance B) the t-tests C) chi-square test D) Pearson correlation
chi-squared test
The most common measure of effect size for the correlation coefficient is called
coefficient of determination
A statistical procedure used to describe the strength and direction of the linear relationship between two factors is called
correlation
Which of the following measures of effect size can be reported with a 3 × 4 chi-square test for independence?
cramer's v
Which of the following would not be reported for a correlation? A) sample size B) coefficient of determination C) critical values for each test D) strength and direction of correlation
critical values for each set
The sign (+ or -) of a correlation coefficient indicates the________________________________ of a relationship between two factors.
direction
Many nonparametric tests are called ________ because they make no assumptions regarding the shape of the distribution in the population.
distribution free tests
When at least one categorical variable has more than two levels, Cramer's V is used to estimate _______________________ for a chi-square test for independence.
effect size
The assumption that there is an equal variance or scatter of data points dispersed along the regression line is referred to as
homoscedasticity
The observed frequencies can be summarized,
in a table in a figure in the main text
A researcher can correct for having expected frequencies smaller than five by
increasing the number of cells increasing the sample size
One way a researcher can correct for having expected frequencies smaller than five is to increase the levels of the categorical variable such that the number of levels
is greater than four
One way a researcher can correct for having expected frequencies smaller than five is to increase the sample size such that
it is five times larger than the number of cells
The degrees of freedom for a chi-square goodness-of-fit test are
k-1
A researcher computes a 4 × 4 chi-square test for independence and estimates the following effect size: V = 0.36. This effect size is
large
Which of the following is the assumption that the best way to describe the pattern of data is using a straight line?
linearity
In a chi-square test, one assumption that must be met concerns the expected frequencies for any give cell. What is this assumption?
must be at least 5
Give an example of two variables that might be related and that would best be tested with a chi-square test of independence.
nominal scale variables
A researcher conducts two chi-square tests. The 2 × 2 chi-square was x^2 = 3.82. The 2 × 3 chi-square was x^2 = 5.02. Which chi-square test resulted in a decision to reject the null hypothesis at a .05 level of significance?
none; both chi square tests result in a decision to retain the null hypothesis
What is the key assumption for a chi-square goodness-of-fit test?
observed frequencies are independently recorded in each cell
The point-biserial correlation coefficient is a measure of the direction and strength of the linear relationship between two variables, where
one is continuous, and one os dichotomous
The sign test is used as a nonparametric alternative to which parametric test?
one sample test related samples t test
When finding the critical value in a chi-square distribution, how many tails do you look in for the cutoff?
one tail
The Spearman correlation coefficient is used to measure the correlation between two variables that are measured on a(n) _______________________ scale.
ordinal
The Spearman rank-order correlation coefficient is a measure of the direction and strength of the linear relationship between two ________ variables.
ordinal
To summarize the chi-square test for independence, report the test statistic, degrees of freedom, observed frequencies (or percentages), effect size, and the_______________________value.
p
correlation coefficient used to test relationship between height and weight
pearson r
The ______________________ correlation coefficient is used to measure the correlation between two dichotomous variables
phi
correlation coefficient used to test relationship between retirement status and death penalty view (pro vs con)
phi
correlation coefficient used to test relationship between retirement status (yes or no) and blood pressure
point biserial
We convert r to a t statistic for which of the following correlation tests?
point-biserial
A major weakness in using a nonparametric test like chi square when a parametric test could validly be used is that the nonparametric test is lower on ______________________________.
power
Which of the following is an appropriate measure of effect size for a 2 × 2 chi-square test for independence?
proportion of variance phi coefficient cramer's V
We compute the frequency expected in each category using known ________ stated in the null hypothesis.
proportions
Which of the following indicates the strongest correlation? A) r = -0.57 B) r = +0.78 C) r = -0.90 D) r = +0.88
r= -0.90
A researcher measures the correlation between gender and student aptitude scores from 0 to 100 among 20 participants. If rpb = 0.49, then what is the decision for this correlation test?
reject the null hypothesis
A researcher measures the correlation of the time it take participants to complete two tasks purported to measure the same cognitive skill. Participant times are converted to ranks from fastest to slowest. If SD^2 = 165 and n = 20, then what is the decision for this correlation test?
reject the null hypothesis
When the chi-square test for independence is significant, this indicates that two variables are__________________________
related (or dependent or correlated)
The Wilcoxon signed-ranks T test is used as a nonparametric alternative to which parametric test?
related samples t test
A researcher observes a correlation of values from 2 to 10 points and draws conclusions about the full range of values in the population from 0 to 21 points. Which limitation for correctly interpreting a correlation coefficient did the researcher violate?
restriction of range
A researcher computes the following phi correlation coefficient: r = 0.42. If the sample size was 20, then what is the decision for this correlation test?
retain null hypothesis
correlation coefficient used to test relationship between rankings of runners on place (1st-8th) and birth order (1st-8th)
spearman
Outliers can change the _____ of a correlation.
strength direction sign (+,-)
To summarize correlations, we report:
strength of correlation direction of correlation p value
The correlation coefficient is used to measure the ________ and ________ of the linear relationship between two factors.
strength; direction
To summarize the chi-square goodness-of-fit test, which of the following is reported?
test statistic p value degrees of freedom
A researcher conducts two chi-square tests. The 2 × 2 chi-square was x^2 = 3.92. The 2 × 3 chi-square was x^2 = 5.92. Which chi-square test resulted in a decision to reject the null hypothesis at a .05 level of significance?
the 2 x 2 chi square
The formula for the Spearman correlation coefficient was derived from the formula for___________________________________________________________
the Pearson correlation coefficient (or just "Pearson r")
As a general rule, the larger the degrees of freedom for a chi-square test,
the larger the critical value will be
Which of the following is a key assumption for a chi-square goodness-of-fit test?
the observed frequencies are independently recorded in each cell
The appropriate correlation coefficient for measuring for the direction and strength of the linear relationship between two dichotomous variables is
the phi correlation coefficient
The appropriate correlation coefficient for measuring the direction and strength of the linear relationship between two ranked or ordinal variables is
the spearman correlation coefficient
If the expected frequencies equal to observed frequencies for a chi-square test for independence, what do we conclude?
the test statistic value is equal to 0
A correlation of r = .38 in a sample of 30 participants is statistically significant for a two-tailed test at a .05 level of significance. (T/F)
true
The coefficient of determination is mathematically equivalent to eta-squared. (T/F)
true
The Mann-Whitney U test is used as a nonparametric alternative to which parametric test?
two-independent sample t test
The denominator of the correlation coefficient measures the extent to which two variables
vary independently
The numerator of the correlation coefficient measures the extent to which two variables
vary together, covary
