PSYC 301 STUDY

The value of X = 9 in the distribution below is the _____.

Minor Mode (The second point of bimodal)

The following table shows the results of an analysis of variance comparing three treatment conditions with a sample of n = 7 participants in each treatment. Note that several values are missing in the table. What is the missing value for MSbeetween? Source SS df MS Between 20 xx xx F = xx Within xx xx 2 Total xx xx

10

In a population of N = 10 scores obtained for a discrete variable for which 0 is not a possible score, the smallest score is X = 8 and the largest is X = 20. What is the range for this population?

12

​ What is the value of the estimated standard error for the following set of D-scores? Scores: 2, 2, 10, 2

2

The following table shows the results of an analysis of variance comparing four treatment conditions with a sample of n = 5 participants in each treatment. Note that several values are missing in the table. What is the missing value for MSwithin? Source SS df MS Between 30 xx xx F = xx Within xx xx xx Total 62 xx

2.

​ An ANOVA is used to evaluate the mean differences among three treatment conditions with a sample of n = 12 participants in each treatment. For this study, what is dfwithin treatments?

33

A research study comparing three treatments with n = 5 in each treatment produces T1 = 5, T2 = 10, T3 = 15, with SS1 = 6, SS2 = 9, SS3 = 9, and Σ X 2 = 94. For this study, what is SStotal?

34

An independent-measures study produces sample means of M 1 = 20 and M 2 = 17. If both samples have n = 18 scores and Cohen's d = 0.50, what is the value for the pooled variance?

36

For an analysis of variance comparing four treatments, MSbetween = 12. What is the value of SSbetween?

36

For a repeated-measures study comparing two treatment conditions, a researcher obtains a sample of n = 9 difference scores with a mean of MD = 4 and a variance of s2 = 36. What is the value for the repeated-measures t statistic for these data?

4/2

For a population with µ = 40 and σ = 5, compute the z-score corresponding to each of the following X values: 41, 47, 33, 28

41=.2 47=1.4 33=-1.4 28=-2.4

A population is the set of all individuals of interest in a particular study.

A True

For any distribution, what is the z-score corresponding to the mean?

A. 0

Calculate each value requested for the following set of scores. A. ΣX B. ΣY C. ΣXΣY D. ΣXY XY 1 0 2 4 3 -1 5 -2

A. 11 B. 1 C. 11 D. -5

Which response option below is consistent with the standard deviation for the population of N = 10 scores depicted below? 2, 2, 5, 5, 6, 6, 7, 8,9,10

A. 2.53

For the following frequency distribution of quiz scores, how many individuals took the quiz? X f 5 6 4 5 3 5 2 3 1 2

A. 21

For the following distribution of quiz scores, how many individuals had a score of X = 4? X f 6 1 5 6 4 4 3 4 2 2 1 2

A. 4

If an entire population with µ = 60 and σ = 8 is transformed into z-scores, then the distribution of z-scores will have a mean of _____ and a standard deviation of _____.

A. U=0 o=1

What is the total number of scores for the distribution shown in the following table? X f 4 7 3 5 2 4 1 2

B. 18

A population of N = 10 scores has µ = 21 and σ = 3. What is the population variance?

B. 9

On an exam with µ = 52, a person has a score of X = 44. Which value for the standard deviation would give this person the highest position in the class distribution?

C, standard deviation is 8

Barbara is a psychologist who measures relationship satisfaction among couples by observing non-verbal behavior (e.g., smiling, mimicking partner actions). In this example, non-verbal behavior is an example of a(n) _____.

C. Operational Definition

A researcher is interested in average first semester change in weight (gain or loss) for students at a local college. Thus, they record the individual change in weight for a small group of 25 freshman from this college during their first semester. Then, the researcher calculates the average change in weight during the first semester among these 25 students. The average is an example of a ______.

C. Statistic

A population of N = 5 scores has a mean of µ = 20 and a standard deviation of σ = 4. Which of the following is the correct interpretation of the standard deviation?

D. d. The average distance of scores from the mean of µ = 20 is 4 points.

A recent study uncovered a correlation between gum disease and heart disease. This result indicates that gum disease causes individuals to develop heart disease.

False

For the following distribution of scores that come from a continuous variable, the upper real limit for the interval that includes X = 2 is 2. X f 5 3 4 2 3 5 2 1 1 3

False

For the following frequency distribution of quiz scores, 10% of students have scores of X = 2. X f 5 4 4 4 3 6 2 4 1 2

False

The value of ΣX + 1 for the scores 1, 0, 2, and 4 is 10.

False

Using the average score to describe a sample is an example of an inferential statistic

False

​ If an analysis of variance is used for the following data, what would be the effect of changing the value of SS2 to 100? Sample Data M1 = 15 M2 = 25 SS1 = 90 SS2 = 70

Increase SS within and decrease the f-ratio

Compute the mean, median, and mode for the set of scores presented in the following frequency distribution table. X f 7 1 6 4 5 3 4 1 3 1 2 2 1 3

Mode = 6 Mean 4 Median= 5

​ In an analysis of variance, which of the following is not true?

Ms total = Ms Between + Ms within

​ In an analysis of variance, which of the following is determined by the size of the sample mean differences?

SS between

Tom scores an X = 43 on an exam with a mean of µ = 52. Tom's score is associated with a z-score of -1.80. What is the value for the exam standard deviation?

Standard deviation of 5

What value is estimated with a confidence interval using the repeated-measures tstatistic

The mean for a population of difference scores

Briefly explain the advantages and disadvantages of using a repeated-measures design as opposed to an independent-measures design.

The repeated-measures design can be a better tool than an independent measures design, this is because the repeated measures design requires fewer test subjects. It is also a way for researchers to study changes over time. It is a design that also reduces the influence of individual differences and has less variability in score. However, there are a few disadvantages with this test. For example there has to be careful attention paid to influences such as order effects. There is also the ability that outside factors may influence a change in scores, such as tutoring when looking at exam scores.

​ What is assumed by the homogeneity of variance assumption?

The two populations have equal variances

If other factors are held constant, which of the following sets of data is most likely to satisfy the homogeneity of variance assumption?

There other 3 options are equally likely to satisfy the assumption

Describe the circumstances in which post hoc tests are used, and explain why these tests are necessary.

These tests are used when you reject the null hypothesis stating that there is at least one difference among more than two treatment conditions. These tests are necessary to find exactlyA. where the difference occur, in other term it is there to find which treatment conditions are different

A researcher conducts an ANOVA to evaluate the mean difference between two treatments using the data from an independent-measures study and obtains F = 4.00. If the researcher had used an independent-measures t test, then t would be t = 2.00.

True

Although a repeated-measures study measures two scores for each participant, the sample mean and variance are computed using only one score for each participant

True

Consider the following scores: 15, 33, 41, 29, 18, 47, 21, 26. The stem and leaf display below accurately represents these scores. 1 58 2 916 3 3 4 17

True

One concern for a repeated-measures study is that a participant's score in one treatment may be influenced by practice or experience gained in a previous treatment

True

​ An ANOVA is used to determine whether any significant difference exists between treatment means, and posttests are used to determine exactly which treatment means are significantly different.

True

​ For an ANOVA, if SSbetween = 40 and SSwithin = 60, then η2 = 40/100

True

​ If a set of n = 9 difference scores has a mean of MD = 3.5 and a variance of s 2 = 36, then the sample will produce a repeated-measures t statistic of t = 3.5/2.

True

Scores on the SAT form a normal distribution with a mean of µ = 500 and standard deviation of σ = 100. If the state college only accepts students who score in the top 60% on the SAT, what is the minimum score needed to be accepted?

X= 475

Using z-scores, a population with µ = 37 and σ = 6 is standardized so that the new mean is µ = 50 and σ = 10. After the standardization, one individual has a score of X = 55. What was this individual's score in the original distribution?

X=40

For a sample with M = 50 and s = 12, what is the X value corresponding to z = -0.25?

X=47

For a population with µ = 65 and σ = 4, what is the X value corresponding to z = -2.25?

X=56

On an exam with a mean of µ = 80, a person scores X = 90. Which of the following values for the standard deviation would position this person highest within the class?

a. σ = 2

What is the average value expected for the independent-measures t statistic if the null hypothesis is true?

a. 0

An independent-measures study with n = 6 in each sample produces a sample mean difference of 4 points and a pooled variance of 12. What is the value for the tstatistic?​

a. 2

What the variance for the following sample of n = 3 scores? Scores: 1, 4, 7

a. 9

Which set of sample characteristics is most likely to produce a significant value for the independent-measures t statistic and a large effect size?

b. A large mean difference and small sample variances

One sample has a variance of s2 = 10 and a second sample has a variance of s2 = 6. Which of the following most accurately describes the pooled variance for the two samples?

b. somewhere between 6 and 10

Of the following options, which of the following is done first in the order of operations?

c. Squaring

When calculating the standard deviation, it is customary to round to _____ decimal point(s)

c. Two

A sample of n = 4 scores, has ΣX = 4, and ΣX2 = 32. What is the value of SS for this sample?

d. 28

Students in an introductory art class are classified as art majors and non-art majors. Which scale of measurement is being used to classify the students?

d. Nominal

A characteristic, usually a numerical value, which describes a sample is called a _____.

d. Statistic

One sample of n = 8 scores has a variance of s2 = 6 and a second sample of n = 8 scores has a variance of s2 = 10. If the pooled variance is computed for these two samples, then the value obtained will be ______.​

exactly halfway between 6 and 10

A repeated-measures study and an independent-measures study both produce a tstatistic with df = 20. The repeated-measures study used more subjects than the independent-measures study.​

false

A research report presents the results of an independent-measures ANOVA as follows: F (3, 28) = 5.36, p < .01. The research study used a total of 31 participants

false

If an independent-measures t statistic has df = 20, then a total of 18 individuals participated in the research study.

false

If two separate samples have M1 = 10 and M2 = 18 with a pooled variance of 16, then Cohen's d = 0.50.

false

​ If an analysis of variance produces a value of F = 1.00, then all the samples have the same mean.

flase

For the repeated-measures t statistic, df = _____.

n-1

A normal distribution has a mean of µ = 40 with σ = 8. If one score is randomly selected from this distribution, which is the probability that the score will be less than X = 34?

p=.2266

A normal distribution has a mean of µ = 90 with σ = 8. If one score is randomly selected from this distribution, which is the probability that the score will have a value between X = 80 and X= 102?

p=.8276

A researcher tests their new treatment for sleep disorder among an individual that has a sleep disorder. The researcher knows that individuals diagnosed with sleep disorder tend to have sleep quality scores that form a normal distribution with µ = 40 and σ = 6. The researcher finds that this individual has a sleep quality score of X = 53 following treatment. Which is the probability that a score this large or larger would be obtained if the new treatment had no effect?

p=0.0150

Which of the following characteristics tends to increase the likelihood that a clear difference between two sample means is detected statistically?

small variances within each sample

​ The null hypothesis for a repeated-measures test states:

the entire population will have a mean difference of μD = 0.

Multiplying every score in a sample by a constant value will change the value of the standard deviation.

true

One sample has s2 = 12, and a second sample has s2 = 15. The pooled variance for these two samples will be between 12 and 15.

true

​ A repeated-measures test usually is more likely to detect a real treatment effect than an independent-measures test because the repeated-measures design typically has a smaller variance and a smaller estimated standard error.

true

​ For a hypothesis test with the independent-measures t statistic, the null hypothesis states that the two population means are the same and the homogeneity assumption states that the two population variances are the same.

true

​ If other factors are held constant, the larger the two sample sizes, the greater the likelihood that the independent-measures t test will find a significant difference.

true

For a population with a standard deviation of σ = 5, what is the z-score corresponding to a score that is 9 points above the mean?

z=+1.80

You are instructed to subtract 2 points from each score, square each of these resulting values, and then find the sum of these squared values. How would this set of instructions be expressed in summation notation?

Σ(X - 2)^2

In general, what characteristics of the difference scores are most likely to produce a significant t statistic for the repeated-measures hypothesis test?

​A large number of scores and a small variance

If one score is randomly selected from a normal distribution with µ = 100 and σ = 20, the probability of obtaining a score between X = 80 and X = 120 is p = 0.6826.

A. True

A set of scores ranges from a low of X = 25 to a high of X = 33 and has a mean of 29. Which of the following is the most likely value for the standard deviation for these scores?

B. 2 points

A researcher predicts that scores in treatment A will be higher than scores in treatment B. If the mean for the 10 participants in treatment A is 4 points higher than the mean for the 10 participants in treatment B and the data produce t = 2.095, what decision should be made?​

B. ​With α = .05, reject H0 for a one-tailed test but fail to reject for a two-tailed test

For the following distribution of quiz scores, if a score of X = 4 or lower is a failing grade, how many individuals failed the quiz? x f 6 3 5 6 4 5 3 5 2 3 1 2

C. 15

A line graph can be used to graphically represent mean or median values for a data set when the values of a variable are measured using either a(n) _____ scale of measurement.

C. interval or ratio

A repeated-measures experiment and a matched-subjects experiment each produce a t statistic with df = 10. How many individuals participated in each study?

D. 11 for repeated and 22 for matched

What is the value of Σ(X + 1)^2 for the scores 0, 1, 2, 4?

D. 39

A sample of n = 12 scores ranges from a high of X = 7 to a low of X = 4. If these scores are placed in a frequency distribution table, how many X values will be listed in the first column?

D. 4

For the following Data, N= X F 4 2 3 3 2 1 1 2

D. 8

A recent study reported that students who just finished playing a prosocial video game were more likely to help others than students who had just finishing playing a neutral or antisocial game. For this study, the kind of game given to the students was the _____.

D. Independent Variable

A sample of scores has a mean of M = 26, a median of 28, and a mode of 29. What is the most likely shape for the sample distribution?

D. Negatively Skewed

Calculate each value requested for the following set of scores. Scores: 1, 3, 4 a. Σ(X - 1) b. ΣX^2 c. (ΣX)^2 d. Σ(X - 1)^2

A. 5 B. 26 C. 64 D. 13

A data set is described as consisting of N = 15 scores. Based on the notation being used, the data set is a sample and contains data from a subset of the population

B. False

Sarah is conducting a research study in which one group of participants consume one cup of coffee, whereas another group of participants consume two cups of coffee. Then, she assesses attention levels of these participants following coffee consumption. This is an example of a(n) _____ research study.

A. Experimental

What is the value of SS (sum of squared deviations) for the following sample? Scores: 2, 4, 5, 9

B. 26

A researcher interested in vocabulary development among toddlers obtains a sample of 2-year-old children to participate in a research study. The average vocabulary development score for the group of toddlers is an example of a parameter.

B. False

A researcher uses an anonymous survey to investigate the television-viewing habits of 100 American adolescents. The researcher plans to make an inference about the television-viewing habits of all American adolescents based on the results of the survey. The entire group of American adolescents is an example of a _____.

B. Population

What additional information is obtained by measuring two individuals on an ordinal scale compared to a nominal scale?

B. The direction of the difference

What additional information is obtained by measuring two individuals on an interval scale compared to an ordinal scale?

B. The size of the difference

Organizing a set of scores in a table or computing an average to summarize a data set is an example of using ______.

B. descriptive Statistics

After a researcher adds 6 points to every score in a sample, the standard deviation is found to be s = 12. The original sample had a standard deviation of s = 6.

B. false

For a sample with M = 40 and s = 4, about 70% of the individuals will have scores between X = 32 and X = 48.

B. false

​ Which of the following possibilities is a serious concern with a repeated-measures study?

The results will be influenced by order effects

A researcher is interested in examining whether self-affirming oneself leads to decreased anxiety in response to threatening information. The researcher conducts a research study in which an individual is self-affirmed prior to receiving threatening information. Researchers know that on average individuals tend to have anxiety levels of µ = 10 with a standard deviation of σ =2 when presented with this threatening information. If a self-affirmed individual has an anxiety level of X = 5 following the threatening message, it is reasonable to conclude that self-affirmation ______.

b. does have an influence on anxiety levels following threatening information

The data below are from an independent-measures experiment comparing three different treatment conditions. Treatment 1 Treatment 2 Treatment 3 0 2 ```4 0 3 2 G = 36 0 1 4 ΣX2 = 114 3 3 3 0 2 4 0 1 4 ------------------------------------- T = 3 T = 12 T = 21 SS = 7.5 SS = 4 SS = 3.5 ​ a. Explain why an ANOVA should be used instead of a series of t tests to evaluate the mean differences among the three treatments. b. Use an analysis of variance with α = .05 to determine whether these data indicate any significant mean differences among the treatments. c. Compute η2, the percentage of variance accounted for by the treatments.

A. A series of t tests creates a higher risk of Type one error. An anova also allows for less work to be performed B. There is a significant difference among these values. The F ratio is in the CR of 3.682 C. The N2 is .643, which means there is a medium effect

For an experiment comparing the effectiveness of two different teaching methods for improving the social skills of autistic children, the dependent variable would be the _____.

A. Levels of improvement in social skills among autistic children

An educational psychologist studies the effect of frequent testing on retention of class material. In one section of an introductory course, students are given quizzes each week. A second section of the same course receives only two tests during the semester. At the end of the semester, both sections receive the same final exam, and the scores are summarized below: Frequent Quizzes Two Exams n = 20 n = 20 M = 73 M = 68 a. If the first sample variance is s2 = 38 and the second sample has s2 = 42, do the data indicate that testing frequency has a significant effect on performance? Use a two- tailed test at the .05 level of significance. (Note: because the two samples are the same size, the pooled variance is simply the average of the two sample variances.) b. If the first sample variance has s2 = 84 and the second sample has s2 = 96, do the data indicate that testing frequency has a significant effect? Again, use a two-tailed test with α = .05. c. Describe how the size of the variance affects the outcome of the hypothesis test

A. The T value is 2.5 which lays in the Cr region of +/-2.024 this shows that there is a significant value. The decision is to reject the Null hypothesis B. The t value is 1.67 which does not lay in the CR of +/-2.024. This means that there is no significant effect and the decision is to fail to reject the null hypothesis

A researcher would like to evaluate the effectiveness of a pain-relief patch designed for lower back pain. Prior to testing the patch, each of n = 8 patients rates the current level of back pain on a scale from 1 to 10. After wearing the patch for 90 minutes, a second pain rating is recorded. The data are as follows: Before After 6 2 8 3 9 4 8 1 10 2 5 3 9 8 7 7 ​ a. Compute the mean and variance for the sample of difference scores. b. Do the results indicate a significant difference? Use a two-tailed test with α = .05 c. Compute Cohen's d to measure the size of the effect.

A. The mean difference is MD= 4 The Variance is 8 B. There is a Signifigant difference as the T score is 4 and the CR is +/- 2.365 and the Null hypothesis is rejected C. Cohen's D is Roughly 1.41

For a normal distribution with a mean of µ = 100 and a standard deviation of σ = 20, find each of the following proportions: a. Proportion of scores greater than X = 107 b. Proportion of scores less than X = 69 c. Proportion of scores less than X = 117 d. Proportion of scores between X = 91 and X = 102

A. Z score= .35 p=.3632 B. Z score= -1.55 p=.0606 C. Z score= .85 p=.8023 D. zscores -.45 & .1 p=.2134

For the following data from a repeated-measures study: a. Find the difference scores b. Calculate MD and the variance for the difference scores c. Calculate the estimated standard error for the mean difference Subject Treatment 1 Treatment 2 A 12 14 B 6 16 C 8 10 D 9 11

A. difference scores are (14-12): 2, (16-6): 10, (10-8): 2, (11-9): 2 B. MD is 16/4 = 4 C. The Estimated standard error for the MD is 1: 48/6= 8 square root of 8/8 is one

A population is normally distributed with µ = 145 and σ = 20. Which is the percentile rank for X = 171?

B. 90.32%

In N = 25 games last season, the college basketball team averaged µ = 83 points with a standard deviation of σ = 8. In their final game of the season, the team scored 78 points. Based on this information, the number of points scored in the final game was _____.

B. A little below average