Stat Psych Final

phi

We convert r to a chi-square statistic for which of the following correlation tests?

Factor B (social activities)

A researcher randomly measures social adjustment among children from different family backgrounds (levels of Factor A: divorced, married, single) who engaged in one of five social activities (Factor B). For this study, 10 children were observed in each group. If SSA = 10, MSB = 12, SSAXB = 48, and SSE = 405, then which effect was significant at a .05 level using the two-way between-subjects ANOVA?

8

"Elementary school children spent significantly more time reading the presence of a teacher than when the teacher was absent, t(7) = 2.804, p < .05." In this related-samples t test, how many participants were observed?

5.74

3. If b = -0.57, MY = 2.75, and MX = 5.25 for a set of data points, then what is the value of the y-intercept for the best-fitting linear equation?

cell

A _____ is the combination of one level from each factor.

frequency polygon; ogive

A ______ is plotted at the midpoint of each interval, whereas a(n) ______ is plotted at the upper boundary (e.g., cumulative) of each interval.

a sampling distribution.

A distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population is called

ordinal

A letter grade (A, B, C, D, F) is an example of _____________ scale.

+1.0

A normal population has μ = 50 and σ = 5. A random sample of n = 25 scores from this population has a mean of 51. What is the z-score for this sample mean?

a one-way between-subjects ANOVA

A professor compared differences in class grades between students in their freshman, sophomore, junior, and senior years of college. If different participants were in each group, then what type of statistical design is appropriate for this study?

to reject the null hypothesis for an upper-tailed test, but to retain the null hypothesis for a two-tailed test

A professor finds that the average SAT score among all students attending his college is 1150 ± 150 (μ ± σ). He polls his class of 25 students and finds that the average SAT score is 1200. Suppose he computes a one-sample z test at a .05 level of significance. What is his decision?

a cumulative frequency distribution from the top down

A psychologist wants to know how many of her clients continue with therapy for at least 12 days. If she constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer her question?

The null hypothesis was rejected and the probability of a Type I error is less than .05.

A research report summarizes the results of the hypothesis test by stating, "z = 2.13, p < .05." Which of the following is a correct interpretation of this report?

The researcher should reject the null hypothesis with α = .05 but not with α = .01.

A researcher administers a treatment to a sample of n = 50 participants and uses a hypothesis test to evaluate the effect of the treatment. The hypothesis test produces a z-score of z = 2.00. Assuming that the researcher is using a two-tailed test,

4.26

A researcher assigned participants (n = 4 per group) to read vignettes describing a person engaging in either a helpful, hurtful, or neutral act. Different participants were assigned to each group and asked to rate how positively they viewed the person described in the vignette. What is the critical value for the one-way between-subjects ANOVA at a .05 level of significance? (You need to find the F critical value from the F-table on the slide.)

compute simple main effect tests for the interaction

A researcher computes a 3 × 4 between-subjects ANOVA and finds one significant main effect and a significant interaction. What is typically the next appropriate step?

2

A researcher computes a 3 × 4 between-subjects ANOVA. What are the degrees of freedom for Factor A for this study?

57

A researcher computes a one-way within-subjects ANOVA in which k = 4 and n = 20. What are the degrees of freedom error for this test?

all of these (a repeated measures design was likely used, the same participants were observed in each group, at least two groups were observed in the study)

A researcher computes a one-way within-subjects ANOVA, thus ______.

The probability of committing a Type I error if we reject the null hypothesis is 3%

A researcher computes a test statistic and finds that the p value for this test is .03. What does this result mean?

0.91

A researcher computes an analysis of regression in which MSresidual = 0.82. What is the value of se in this example?

5

A researcher computes the computational formula for SS and finds ON THE BOARD that and ON THE BOARD. If this is a sample of 4 scores, then what would SS equal using the computational formula?

d = 0.74 (medium effect)

A researcher computes the mean difference in locomotion in a sample of 12 rats before and 30 min after an injection of amphetamine. Rats were placed in a box with infrared beams. The number of times rats crossed the beams was used as a measure of locomotion. The mean difference in locomotion was 6.2 ± 8.4 (MD ± SD) and this difference was significant. What is the effect size for this result using estimated Cohen's d?

0.23

A researcher conducts a 2 × 3 between-subjects ANOVA. She finds a significant interaction, where SSAXB = 120 and SST = 518. What is the effect size for this test using η2?

reject the null hypothesis

A researcher conducts a 2 × 4 between-subjects ANOVA in which 12 participants were observed in each group. If SSA = 18 and SSE = 264, then what is the decision for Factor A at a .05 level of significance using the two-way between-subjects ANOVA?

0.38

A researcher conducts a study using the one-way between-subjects ANOVA. He computes SSBG = 120 and SSE = 200. What is the effect size for this test using η2?

Study 2

A researcher conducts two studies on the effectiveness of a peer mentoring program. Self-evaluation ratings among participants before, during, and after the program were measured in both studies. In Study 1, 12 participants were observed, and in Study 2, 16 participants were observed. If Fobt = 3.42 in both studies, then in which study will the decision be to reject the null hypothesis at a .05 level of significance?

Test 2 is associated with larger degrees of freedom

A researcher conducts two t tests. Test 1 is a two-tailed test with a smaller sample size at a .05 level of significance. Test 2 is a two-tailed test with a larger sample size at a .05 level of significance. What do you know about the degrees of freedom for each test?

-1.0

A researcher determines that students study an average of 80 ± 20 (M ± SD) min/week. Assuming these data are normally distributed, what is the z score for students studying 60 min/week?

a one-way between-subjects ANOVA

A researcher divides participants into groups that will engage in low, moderate, or intense levels of exercise. The total calories consumed by participants following the exercise are then recorded. What type of statistical design is appropriate for this study?

a between-subjects factorial design

A researcher has participants complete a survey regarding their level of restraint when eating. Participants were assigned to groups based on their current health status (lean, overweight, obese) and gender (male, female). What type of factorial design is most appropriate for this study?

would be entirely in the left-hand tail of the distribution

A researcher is predicting that a treatment will decrease scores. If this treatment is evaluated using a directional hypothesis test, then the critical region for the test ______.

±2.145

A researcher matched 30 participants on intelligence (hence 15 pairs of participants) and then compared differences in emotional responsiveness to two experimental stimuli between each pair. For this test, what are the critical values, assuming a two-tailed test at a .05 level of significance?

27

A researcher measures attractiveness ratings of a male confederate among 30 women who were told the confederate was either single, dating, or married (n = 10 per group). What are the degrees of freedom for error for the one-way between-subjects ANOVA?

retain the null hypothesis

A researcher measures the amount of high fat foods (in grams) consumed by 8 rat subjects 1 day, 3 days, and 5 days following the introduction of a high fat diet. If SSBG = 30 and SSE = 70 for a one-way within-subjects ANOVA, then what is the decision at a .05 level of significance?

reject the null hypothesis

A researcher measures the correlation between gender and student aptitude scores from 0 to 100 among 20 participants. If rpb = .49, then what is the decision for this correlation test?

.61

A researcher measures the correlation between self-esteem (high or low) and physical fitness scores (continuous) among 24 school athletes. In the study, 12 participants reported high selfesteem and 12 reported low self-esteem. If sY = 9.06 and MY1 - MY2 = 11, then what is the value of the correlation coefficient?

0.66

A researcher measures the correlation in rankings for a sample of restaurants and consumers' rankings of their favorite restaurants. If ∑ 𝐷 2 = 96 and n = 12, then what is the value of the correlation coefficient?

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 ∑ 𝐷 2 = 165 and n = 20, then what is the decision for this correlation test?

the speed at which people eat

A researcher measures the extent to which the speed at which people eat (in minutes) predicts calorie intake (in kilocalories). Which factor is the predictor variable in this example?

perceptions of forgiveness

A researcher measures the extent to which years of marriage predict perceptions of forgiveness. Which factor is the criterion variable in this example?

.01

A researcher measures the following correlation between number of years of education and life satisfaction: r = +.08. What is the value of the coefficient of determination?

0.66

A researcher measures the relationship between narcissism and willingness to help. If SSXY = 240, SSX = 320, and SSY = 410, then what is the value of the correlation coefficient?

histogram

A researcher measures the weight (in ounces) of newborn infants in the month of March. What type of graphical display would be most appropriate for summarizing the frequency of infants falling into different intervals of weight?

4

A researcher observed the mating behavior of 10 porpoises in five different social conditions. What are the degrees of freedom between groups for a one-way within-subjects ANOVA?

residual variation

Using an analysis of regression, the variability in Y that is associated with error is measured by the ______.

mean = 10, standard error = 1

A researcher randomly selects a sample of participants from a population with a standard deviation of 5. If the researcher selects a sample of 25 participants with a mean of 10, then what is the mean and standard error for the sampling distribution of the mean?

Yes

A researcher records the following data for the number of dreams recalled during a night of sleep for 10 college students: 3, 2, 4, 4, 3, 1, 1, 0, 2, and 0. Is the mean equal to the median in this example?

d = 0.88; large effect size

A researcher reports that the mean difference in the body weight of rats following a pharmacological versus control treatment is 14 g, with a pooled sample variance equal to 256. What is the effect size for this test using estimated Cohen's d?

Mean scores shifted 0.88 standard deviations in the population

A researcher reports that the size of an effect in some population is d = 0.88. Which of the following is an appropriate interpretation for d?

3.24

A researcher reports the following equation for a best-fitting straight line to a set of data points: 𝑌̂ = - 1.01𝑋 + 3.24. Which value is the y-intercept?

Satisfaction ratings significantly differ, t(15) = 3.60.

A researcher sampled 16 couples and measured the mean difference in their marital satisfaction. Each couple was paired and the differences in their ratings (on a 7-point scale) were taken. If the mean difference in satisfaction ratings for this sample was 1.8 ± 2.0 (MD ± SD), then what is the decision at a .05 level of significance?

df = 23; it represents the number of scores that are free to vary in a sample

A researcher selects a sample of 24 participants and has them complete a survey on dating preferences. In this example, what are the degrees of freedom for sample variance and what does this represent?

Reject the null hypothesis; IQ scores in this sample are significantly higher than those in the population.

A researcher selects a sample of 36 students from a school population with a mean IQ of 100 and a standard deviation of 12. She determines that the mean IQ in this sample is 104. Assuming she computes a one-sample z test at a .05 level of significance, what is the decision for a two-tailed test?

μ = 70

A researcher selects a sample of n = 30 from a normal population with μ = 70 and σ = 10, and a treatment is administered to the sample. If a hypothesis test is used to evaluate the average effect of the treatment, what is the null hypothesis?

experimental

A researcher tests whether the dosage level of some drugs (low, high) causes significant differences in health. To do this, the researcher randomly assigns rat subjects to receive a low or high dosage of the drug and records health-related measures in both groups. The type of method described is

M = 90 for a sample of n = 100

A sample is selected from a population with μ = 80, and a treatment is administered to the sample. If the sample variance is s2 = 20, which set of sample characteristics is most likely to lead to a decision that there is a significant treatment effect?

t = -3/2 = -1.50

A sample of n = 25 scores has a mean of M = 40 and a variance of s2 = 100. If this sample is being used to test a null hypothesis stating that μ = 43, then what is the t statistic for the sample?

The researcher must fail to reject the null hypothesis with either α = .05 or α = .01.

A sample of n = 25 scores produces a t statistic of t = - 2.05. If the researcher is using a two-tailed test with α = .05, the correct statistical decision is ______.

87-96

A set of scores ranges from a high of X =96 to a low of X = 27. If these scores are placed in a grouped frequency distribution table with an interval width of 10 points, the top interval in the table would be _______.

a correlation

A statistical procedure used to describe the strength and direction of the linear relationship between two factors is called ______.

There is approximately 9% chance of obtaining a sample mean of 21 or lower.

ACT scores are known to have a normal distribution with a population mean of 22 and a population standard deviation of 3. What proportion of sample means will be less than 21 if a sample size of 16 is used?

a significant main effect test and a significant interaction test

An estimate of effect size with the two-way ANOVA is typically reported for ______.

standard error of estimate

An estimate of the standard deviation or distance that data points fall from the regression line is measured by the ______.

d = 4/5

An independent-measures study produce sample means of M1 = 35 and M2 = 31 and a pooled variance of 25. For this study, Cohen's d = ______.

a confound variable

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 ______.

different participants are assigned to each group or cell

Computing a two-way between-subjects ANOVA is appropriate when ______.

3.5

Consider the boxplot below (ON THE BOARD). What is the interquartile range (IQR)?

a 1-between factorial design

Each of the following is a type of two-way ANOVA, except ______.

A = 3.2, B = 13

Fill in the missing values for A and B in this frequency distribution table:

µD = 0

For a repeated-measures hypothesis test, the null hypothesis states ______.

the number of factors in the design

For an analysis of variance, the term "one-way" refers to ______.

a sample of n = 25 scores

For samples selected from a population with μ = 100 and σ = 15, which of the following has the smallest standard error?

comparing pain tolerance before and after taking a new pain medication

For which of the following situations would a repeated-measures research design be appropriate

that the variance is equal in each population from which samples are selected

Homogeneity of variance is an assumption for the one-way between-subjects ANOVA. What does this assumption mean?

The likelihood of rejecting true H0 and the power of the test both decreases.

How does an increase in the value of σ influence the likelihood of rejecting the true null hypothesis and the power of the hypothesis test?

The t distribution is flatter and more spread out, especially when n is small.

How does the shape of the t distribution compare to a normal distribution?

25% of people would score lower than 90 on an IQ test

IQ scores are known to be normally distributed with a population mean of 100 and a population standard deviation of 15. What percentage of people would score lower than 90 on an IQ test?

15.21

If r = .65 and n = 36, then what is the value of x^2 ?

12/sqrt4 = 6 points

If random samples, each with n = 4 scores are selected from a population with μ = 80 and σ = 12, then how much distance is expected on average between the sample means and the population mean?

700

If the coefficient of determination is .30 and the sum of squares regression for an analysis of regression is 210, then what is the value of SSY?

102

If the coefficient of determination is .32 and SSY = 150, then what is the sum of squares residual for an analysis of regression?

0.017

If the experimentwise alpha for three pairwise comparisons is .05, then what is the value for testwise alpha?

all of these. (the value of the test statistic is larger than the critical value, the decision is to reject the null hypothesis, p < .05)

If the value of the test statistic is in the rejection region, then

X does not significantly predict Y.

In a sample of 22 participants, suppose we conduct an analysis of regression with one predictor variable. If Fobt = 2.07, then what is the decision for this test at a .05 level of significance?

the relative contribution of each factor

In addition to evaluating the significance of a multiple regression equation, we also should consider ______.

all of these (X; Y the predictor variable; the criterion variable the known variable; the to-be-predicted variable)

Linear regression describes the extent to which ______ predicts ______.

two or more

Multiple regression is a statistical method that includes ______ predictor variable(s) in the equation of the regression line.

detect the extent to which two or more predictor variables interact

One key advantage for including multiple predictor variables in the equation of a regression line is that it allows you to ______.

7

One sample has n = 10, M = 10 scores. A second sample has n = 15 and M = 5 scores. If the two samples are combined, then the combined sample will have a mean ______.

liberal

Partial η2 is a more ______ estimate of effect size than partial ω2.

inferential statistics

Procedures that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected best describe

all of these (The correlation is positive, The correlation is statistically significant, The coefficient of determination is .08)

Select the description below that identifies the following correlation: r = .28, p < .01.

2.804

Study conducted to test if teacher supervision influences the time that elementary school children read. The study conducted a repeated measure design to 8 students: when teacher present vs. when teacher absent. Let's assume a sum of mean differences is 15 (i.e., ∑D = 120) and a standard deviation of difference scores is 15.12 (SD =15.12). You want to test whether reading times differ at a .05 level of significance. What is the obtained t-statistic?

82.66

Study examining strategy to reduce food intake by eating slower. To test this, two groups are given the same buffet foods to consume: Group Eating Slowly (Mean = 600, SD = 154.92) and Group Eating Fast (Mean = 650, SD = 130.38). Sample sizes are 6 for each group (i.e., equal sample size). What is estimated standard error for the independent t-test?

CI[-234.17, 134.17]

Study examining strategy to reduce food intake by eating slower. To test this, two groups are given the same buffet foods to consume: Group Eating Slowly (Mean = 600, SD = 154.92) and Group Eating Fast (Mean = 650, SD = 130.38). Sample sizes are 6 for each group (i.e., equal sample size). What is the 95% confidence interval for the independent samples t-test using 0.05 alpha?

CI[12.684, 15.136]

Suppose elementary school children in the general population show reading proficiency (μ =12, σ = 4) points on a given standardized measure. If we select a sample of 25 elementary school children in the reading program and record a sample mean in reading proficiency equal to 14 (M = 14) points. What is the 95% Confidence Interval for the One Sample Z test using an alpha level of 0.05?

a population of moviegoers who paid to see the movie in a theater

Suppose that a researcher is interested in a group of 10 million people who paid to see a movie in theaters. In this example, the 10 million moviegoers would be regarded as

ordinal

The Spearman rank-order correlation coefficient is a measure of the direction and strength of the linear relationship between two ______ variables.

it produces a minimal positive solution that is not zero, as long as all scores are not exactly the same value.

The advantage of squaring the deviation of each score from the mean and then summing is that

regression variation

Using an analysis of regression, the variability in Y that is predicted by X is measured by the ______.

the point-biserial correlation coefficient

The appropriate correlation coefficient for measuring the direction and strength of the linear relationship between one continuous and one dichotomous variable is ______.

homoscedasticity

The assumption that there is an equal variance or scatter of data points dispersed along the regression line is referred to as ______.

all of these (a measure of effect size, mathematically equivalent to magic n ^2, equal to the correlation coefficient squared)

The coefficient of determination is ______.

magic n ^2

The coefficient of determination is mathematically equivalent to ______.

all of these (two factors can be observed using the two-way ANOVA, but not using the t tests and the one-way ANOVAs, three hypothesis are made with one statistical test using the two-way ANOVA, but not using the t tests and the one-way ANOVAs, an interaction can be observed using the two-way ANOVA, but not using the t tests and the one-way ANOVAs)

The complexity of the two-way ANOVA differs from that of the t tests and the one-way ANOVAs in that, ______.

related to changes

The correlation coefficient measures the extent to which changes in one factor are ______ in a second factor.

-1, +1

The correlation coefficient ranges between ______ and ______.

n - 2

The degrees of freedom associated with residual variation are equal to ______.

are equal to the sample size minus one

The degrees of freedom for the sample variance

vary independently

The denominator of the correlation coefficient measures the extent to which two variables ______.

provides an estimate of the error associated with the difference scores.

The denominator of the test statistic for a related-samples t test

larger

The distribution of annual household income in the United States is positively skewed. If the median annual income is about $56,000, this implies that the mean annual household income in the Unites States is

sample variance; population variance

The estimated standard error in the t statistic uses the ______ to estimate the ______ when the population variance is unknown.

the p value

The following is a summary of a significant interaction for a two-way ANOVA: F(2, 30) = 2.04, p < .05 (η2 = .15). Assuming the test statistic value is correct, then which of the following must be incorrect in this report?

all of these (data that are normally distributed, data that are on an interval or ratio scale, data in which the mean, median, and mode are equal)

The mean is an appropriate measure of central tendency for

best-fitting

The method of least squares is used to determine the ______ straight line to a set of data points

the total area under the curve is greater than 1.0.

The normal distribution has all of the following characteristics, except that

all of these (the population of X and Y scores are normally distributed, for each X score, the distribution of Y scores is normally distributed, for each Y score, the distribution of X scores is normally distributed)

The normality assumption states that the population of X and Y scores form a bivariate ("two variable") normal distribution, such that ______.

dichotomous

The phi correlation coefficient is a measure for the direction and strength of the linear relationship between two ______ variables.

μ; M

The population mean is symbolized as ______, whereas the sample mean is symbolized as ______.

how far each data point deviates from the line that most closely fits the data

The regression equation measures ______.

are both unbiased estimators.

The sampling distribution of the mean and the sampling distribution of the variance when dividing SS by n - 1.

0; 1

The standard normal distribution is normally distributed with a mean of ______ and a variance of ______.

a simple main effect test

The statistical procedure used to analyze the simple main effects of an interaction is called ______.

observing different participants one time in each group

The term "between-subjects" refers to ______.

find the real range, find the interval width, and construct the frequency distribution.

The three steps for constructing a simple frequency distribution are

unstandardized beta coefficients

The value of b1 and b2 are referred to as ______.

the alpha level

The z-score boundaries for the critical region are determined by ______.

the population variance of difference scores

To compute a related-samples t test, a researcher has to know many values. Which of the following is NOT a value that the researcher must know to compute this test?

the critical values

To summarize a one-way within-subjects ANOVA, we report each of the following except, ______.

A × B interaction

Using a two-way between-subjects ANOVA with Factor A (gender: male, female) and Factor B (type of employment: blue collar, white collar), a researcher found that scores for men and women significantly varied across the levels of the second factor (type of employment). In this study, the researcher found a significant ______.

n participants are observed k times

Using a within-subjects ANOVA design, ______.

If we select a sample at random, then on average we can expect the sample mean to equal the population mean.

What does it mean to say that the sample mean is an unbiased estimator of the population mean?

the square root of the mean square residual

What is the computation for the standard error of estimate?

equal to 1

When the variability attributed to between groups is equal to the variability attributed to error, then the value of the test statistic for a one-way between-subjects ANOVA is ______.

The probability of rejecting a false null hypothesis

Which of the following defines the power of a hypothesis test?

the effects of ones' income level on their resiliency in the face of each of three cognitively-challenging tasks

Which of the following describes a research design in which one factor could be a between-subjects factor, and the second factor could be a within-subjects factor?

𝑌̂ = b1X1 + b2X2 + b3X3 + a

Which of the following equations is appropriate for a linear regression with three predictor variables?

Delete a score above the mean and the mean will increase.

Which of the following is NOT a characteristic of the mean?

Plan experimental designs.

Which of the following is NOT four steps of hypothesis testing?

The t statistic uses the sample variance in place of the population variance.

Which of the following is a fundamental difference between the t statistic and a z-score?

Multiplying each score times the same constant will change the standard deviation by that constant.

Which of the following is a property of the standard deviation?

A large sample and a small value for σ.

Which of the following is most likely to reject the null hypothesis even if the treatment effect is very small?

SSY

Which of the following is not needed to compute the slope using the method of least squares?

compute a z-transformation and find the probability of a z score in the unit normal table

Which of the following is required to locate proportions of area under the normal curve?

linearity

Which of the following is the assumption that the best way to describe the pattern of data is using a straight line?

the mean difference observed minus the mean difference stated in a null hypothesis

Which of the following is the numerator of the test statistic for the related-samples t test?

method of least squares

Which of the following is used to determine the linear equation that best fits a set of data points?

Bonferroni test

Which of the following post hoc tests can be used with the related-samples t test?

Tukey's HSD test

Which of the following post hoc tests is associated with the least power to detect an effect?

Compare the mathematics skills for 9th grade boys versus 9th grade girls

Which of the following research situations would be most likely to use an independent-measures design?

n = 16 with s2 = 400

Which of the following samples will produce the largest value for the estimated standard error?

The central limit theorem only works when the sample size is greater than 100.

Which of the following statements about a central limit theorem is NOT true?

The mean ranges from -3 to 3

Which of the following statements about a normal distribution is NOT true?

If the SE is large, your sample statistic is reliable and accurate

Which of the following statements about a standard error of mean is NOT true?

The closer that data points fall to the regression line, the more the variance in Y will be attributed to regression variation.

Which of the following statements is true regarding the sources of variation present in an analysis of regression?

change α from .01 to .05

Which of the following will increase the power of a hypothesis test?

Doing so makes the sample variance an unbiased estimator of the population variance.

Why is it important to divide by df (i.e., n-1) to compute sample variance?

the number of employees who work under the employer

You are interested in measuring the construct, work expertise. Which of the following measures for this construct is quantitative and discrete?