WSU PSYCH 311 EXAM 3 STUDY GUIDE
we only test
H0
we do not test
H1
computing pooled variance
S2p=SS1+SS2/df1+df2
Basic Statistics
Standard deviation, mean, median, mode, variability
family of t distributions
a series of sampling distributions (of the t statistic) developed by Gossett. The shape of any one distribution is a function of sample size (or degrees of freedom, equal to n-1)
CL = + or - + means that
all CR falls in upper tail
CL = + or - - means that
all CR in lower tail
mixed factoral design
both within subjects and between subjects
rm anova
comparing relationships with 1 factor and more than 2 groups
df=n-1
critical level that defines critical region
words that describe <
decline, worse, fewer, decrease, less than, negative change
S(M1-M2)
denominator
main effect
effect of 1 IV in isolation
paired samples design
experimental design in which scores from each group are logically matched
H1 > (greater) you can expect
large value for t
significance levels of Tukey
significant if above the tukey level
if you dont have o-(standard deviation) or o-m but have s or Sm(estimated standard error + denominator) then you are dealing with a ____
single sample t-test
3. A method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called A) guessing B) hypothesis testing C) random sampling D) level of significance
B
14. The ________ is an inferential statistic used to determine the number of standard deviations in a t distribution that a sample mean deviates from the mean value or mean difference stated in the null hypothesis. A) degrees of freedom B) t distribution C) t statistic D) standard error
C
8. A researcher obtains z = 1.45 for a one-sample z test. What is the decision for this test at a .05 level of significance? A) It depends on whether the test is one-tailed or two-tailed. B) to reject the null hypothesis C) to retain the null hypothesis D) There is not enough information to make a decision.
C
15. The t distribution is similar to the z distribution except A) it is associated with scores being more likely in the tails of the distribution B) it is associated with greater variability C) it is characterized by "thicker" tails compared with the z distribution D) all of the above
D
21. Computing a one-sample t test is appropriate when A) the population variance is unknown B) participants are observed one time C) participants are assigned to only one group D) all of the above
D
Cohen's d
a measure of effect size that assesses the difference between two means in terms of standard deviation, not standard error
within-subjects design
a research design that uses each participant as his or her own control; for example, the behavior of an experimental participant before receiving treatment might be compared to his or her behavior after receiving treatment
One-way ANOVA
comparing relationships with 1 factor and more than 2 groups
17. State the critical value(s) for a t test using a two-tailed test at a .05 level of significance: t(20). A) B) C) D)
A
between-subjects design
A research design in which different groups of participants are randomly assigned to experimental conditions or to control conditions.
repeated measures design
An experiment using a within-groups design in which participants respond to a dependent variable more than once, after exposure to each level of the independent variable.
13. Hypothesis testing is also called A) random testing B) effect size C) significance testing D) Type III error
C
FTR
H0 is true, the observed outcome is due to sampling error
test statistic formula
Used to decide whether or not to reject H0 test statistic= change difference, relationship obtain or observed in sample data/change difference, relationship expected due to sampling error.
interaction
combined effect of all IV's
natural difference
individual differences
r squared = .5
large
Reject hypothesis when
numerator is bigger than the denominator
generic test stat formula
observed difference /(divided by) difference due to change
words that describe an independent samples test:
separate samples/groups, independent, different group, control & treatment groups
Platykurtic
short and wide
3x2 shows that
2 independent variables, one with 3 groups and the other with 2 groups
factorial anova
2 or more iv's, how ever many dv's per iv
11. When reporting the results of a one-sample z test using APA format, the ________ do/does not need to be reported. A) critical values B) effect size C) Test statistic D) p value
A
29. Which of the following summarizes a t test that was significant and associated with a large effect size? A) t(12) = 2.95, p < .05, d = .82 B) t(22) = 3.02, p < .05, d = .36 C) t(30) = 1.03, p > .05, d = .20 D) t(60) = 1.76, p > .05, d = .45
A
4. Which of the following is not one of the four steps to hypothesis testing? A) evaluate the plan B) compute the test statistic C) state the hypotheses D) set the criteria for a decision
A
The t-distribution is a.Symmetrical with a mean of 0. b.Always normal in shape. c.Symmetrical with M ≈ µ. d.Mostly leptokurtic.
A
if the sign is -
opposite direction
independent samples
positively skewed, mean of 1, and only positive values
effect size
r squared
t statistic formula
t = (M-u) / Sm
fail to reject the null hypothesis when
the denominator is bigger than the numerator
if your H1 is =/ then it is (=/ meaning it cannot predict differences of direction)
two tailed
sampling error in ms within
type 1
positive/negative .5
weak
Hypothesis Testing Steps
1. Check Assumptions 2. Hypotheses 3. use sample data to collect an estimate of that parameter 4. Compare your estimate to the claim (critical value) 5. Make a conclusion about the claim (reject or fail to reject)
50. Which design allows you to test an interaction effect? A) a two-way ANOVA B) an independent groups t-test C) a one-way ANOVA D) All of the above
A
52. (EXTRA CREDIT) A researcher assigned participants (n = 8 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? A) 3.47 B) 4.32 C) 3.44 D) 3.07
A
In general, a small value (near zero) for a t-statistic will result in... a.Failing to reject the null hypothesis. b.Rejecting the null hypothesis. c.Accepting the null hypothesis. d.Accepting the alternative hypothesis.
A
Which of the following accurately describes an independent-samples study? a.It uses a different group of participants for each of the treatment conditions being compared. b.It uses the same group of participants in all of the treatment conditions being compared. c.It uses one group of participants to evaluate a hypothesis about one population mean. d.None of these is correct.
A
Which of the following samples will almost certainly lead us to fail to reject the null hypothesis? a.Md = 2 and Smd = 10 b.Md = 2 and Smd = 2 c.Md = 10 and Smd = 10 d.Md = 10 and Smd = 2
A
Independent Samples Design
A design in which two separate groups are compared: the sample is divided into one experimental group vs. one control group
pooled variance
A weighted average of the two estimates of variance—one from each sample—that are calculated when conducting an independent-samples t test.
estimated standard error
An estimate of the standard error that uses the sample variance (or standard deviation) in place of the corresponding population value.
12. Is a one-sample z test reported differently for one-tailed and two-tailed tests? A) It can be reported differently when the effect size is large. B) No, the same values are reported. C) It depends on whether the results were significant. D) Yes, only significant results for a two-tailed test are reported.
B
34. A researcher records the time it takes (in seconds) for participants to respond (by pressing a key) to a familiar versus an unfamiliar word flashed onto a computer screen. In this study, the difference in response time for each participant is compared. The type of design described here is called a A) mixed measures design B) repeated measures design C) independent samples design D) matched samples design
B
42. A researcher compares differences in positivity between participants in a low-, middle-, or upper-middle-class family. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA? A) (3, 12) B) (2, 42) C) (2, 12) D) (3, 43)
B
43. Computing a one-way between-subjects ANOVA is appropriate when A) the levels of one or more factors are manipulated B) different participants are observed one time in each of two or more groups for one factor C) the same participants are observed in each of two or more groups for one factor D) all of the above
B
A repeated-measures study would NOT be appropriate for which of the following situations? a. A researcher would like to study the effect of practice on performance. b. A researcher would like to compare individuals from two different populations. c. The effect of a treatment is studied in a small group of individuals with a rare disease. d. A developmental psychologist examines how behavior unfolds by observing the same group of children at different ages.
B
A researcher conducts a research study comparing two treatment conditions and obtains 20 scores in each condition. If the researcher used a repeated-measures design, how many subjects participated in the research study? a. 10 b. 20 c. 21 d. 40
B
A researcher uses a repeated-measures design with n = 15. What will the df be in this t-test? a.df = 29 because there are 30 scores and 30 - 1 = 29. b.df = 14 because there are 15 participants and 15 - 1 = 14. c.df = 28 because there are two sets of 15 scores and DFtotal = DFfirst-set + DFsecond-set = 14 + 14 = 28.
B
Researchers believe that a new drug will improve memory in older adults with early-onset Alzheimer's disease. The researchers compare a sample of n = 12 participants with early-onset Alzheimer's to the population of older adults without early-onset Alzheimer's. They use a standardized measure of memory in which µ = 45. A single-sample t-test yields a value of t = -2.33. The critical level for the test was t = 1.796. What can the researchers conclude about the drug? a. Because their t-test value fell within the critical region, they can conclude that the drug is effective. b. Because their t-test value did not reach the critical level, they can conclude that the drug is not effective. c. Because their t-test value fell in the extreme negative end of the t-distribution, they can conclude that the drug impaired memory. d. A conclusion cannot be determined without additional information.
B
16. The estimated standard error in the t statistic uses the ________ to estimate the ________ when the population variance is unknown. A) population variance; sample variance B) degrees of freedom; sample size C) sample variance; population variance D) standard error; sample variance
C
41. For an analysis of variance, the term "one-way" refers to A) the number of statistical tests in the design B) the direction that traffic should follow on a road C) the number of factors in the design D) the number of ways that the data can be analyzed
C
9. ________ allows researchers to describe (1) how far mean scores have shifted in the population, or (2) the percentage of variance that can be explained by a given variable. A) Power B) Significance C) Effect size D) Probability
C
If a researcher reports a single-sample t-test with df = 18, how many individual subjects participated in the experiment? a. n = 17 b. n = 18 c. n = 19 d. cannot be determined
C
The alternative hypothesis for an independent-measures t-test states _____. a.There is no mean difference between the two populations being compared b.There is no mean difference between the two samples being compared c.There is a non-zero mean difference between the two populations being compared d.There is a non-zero mean difference between the two samples being compared
C
Which of the following is NOT a measure of sampling error? a. σm b. s(M1-M2) c. σ d. Smd
C
Which of the following is the null hypothesis for an independent-samples t-test? a. H0: M1 - M2 = 0 b. H0: M1 - M2 ≠ 0 c. H0: µ1 - µ2 = 0 d. H0: µ1 - µ2 ≠ 0
C
how to compute cohen's d to measure the size of the effect
Cohen's d is determined by calculating the mean difference between your two groups, and then dividing the result by the pooled standard deviation
33. For the related samples t test, assuming that all other values remain constant, then as samples size increases, A) the power to detect an effect increases B) the estimate for standard error decreases C) the value of the test statistic increases D) all of the above
D
37. Compared to the two-independent sample t test, the related samples design decreases A) effect size B) significance C) power D) standard error
D
40. What is the definition of "power" in statistics usage? A) The likelihood of retaining a true null hypothesis B) The likelihood of rejecting a true null hypothesis C) The likelihood of retaining a false null hypothesis D) The likelihood of rejecting a false null hypothesis
D
49. A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the MSE ? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122 A) 8 B) 0.125 C) 0.50 D) 2
D
51. (EXTRA CREDIT) 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 salary for men and women significantly varied across the levels of the second factor (type of employment). That is, the effect of gender depended on type of employment. In this study, the researcher found a significant A) post hoc test B) main effect of Factor A C) main effect of Factor B D) interaction
D
A(n) _____ t-test is used when you can find µ from theory and estimate σ from s. a.Independent-samples b.Repeated-measures c.Paired-samples d.Single-sample
D
An educational psychologist studies the effects of frequent testing on retention of course material. In one class, students (n = 38) take one quiz per week and a cumulative final exam. In the other class, students (n = 29) take one mid-term and a cumulative final exam. At the end of the semester, the educational psychologist compares the scores on the final exams (assume higher scores on the exam indicate greater retention of course material). *****The df used for this test are _____.***** a. 68 b. 67 c. 66 d. 65
D
The formula, M1-M2/S(M1-M2) describe which of the following? a. The effect size measure for an independent-samples t-test. b. The estimated standard error for an independent-samples t-test. c. The repeated-measures t-test. d. The independent-samples t-test.
D
To calculate a t-statistic, what information is needed from the sample? a. The value for n b. The value for M c. The value for s or s2 d. All of the above
D
Which of the following is NOT needed to find the critical level(s) that defines the critical region(s)? a.The α-level. b.The n of the sample. c.Whether the t-test is a one-tailed or two-tailed test. d.Whether the t-test is a single-sample t-test, an independent samples t-test, or a repeated-measures t-test.
D
RM t test
D=X2-X1 (2=post test 1=pretest)
matched-subjects design
Each individual in one sample is matched with an individual in the other sample. the matching is done so that the two individuals are equivalent (or nearly equivalent) with respect to a specific variable that the researcher would like to control.
"improve" CL = + 2.82 t = -2.98 example of ____
FTR (failure to reject)
Type 1 error
False positive. There is no difference between groups and you report there IS
rejecting hypothesis
H0 is false, the observes outcome is due to the true effects of the study.
Sm matches ___
M-u(population mean; (mu)
note that S(M1-M2)(denominator) matches ___
M1-M2
Critical Value of a Test Statistic
The value of a test statistic that corresponds to a specified level of chance probability
family of t-tests
There are three t-tests that we'll discuss: single-sample t-test, independent-samples t-test, and repeated-measures t-test. These share common features, but are used in distinctly different situations.
Under what circumstances is a T Statistic used instead of a z-score for a hypothesis test?
When the population standard deviation and variance are not known.
single sample t test
a hypothesis test in which we compare a sample from which we collect data to a population for which we know the mean but not the standard deviation
independent samples t-test
a hypothesis test used to compare two means for a between-groups design, a situation in which each participant is assigned to only one condition
sample level standard deviations
biased approximation of the population-level standard deviation (σ). We correct the bias by using df = n - 1 to calculate s.
degrees of freedom
describe the number of scores in a sample that are independent and free to vary.
type 2 error
false negative; fails to perceive an effect that is there
f statistic
if you reject the null then we expect there to be treatment differences which means we expect f to be greater than 1--> no treatment conditions (fail to reject null) then F should be about equal to 1
words that describe >
improved, better, more, greater than, positive change
population -> S1 and S2
independent sample test
estimated standard error (Sm)
is used as an estimate of the real standard error, σM, when the value of a is unknown. It is computed from the sample variance or sample standard deviation and provides an estimate of the standard distance between a sample mean, M, and the population mean, u.
0
no correlation
M1-M2 is the
numerator
words that describe a single sample test:
one sample, compared to population
if you have CL = + or - then it is
one tailed
if the sign is +
same direction
r squared = .10
small
t distribution
the complete set of t values computed for every possible random sample for a specific sample size or a specific degrees of freedom
sample statistic
the value of a variable that is estimated from a sample
post hoc
when the null hypothesis is rejected and there are more than two factors-->determines where the differences in sample means comes from (which sample)
Latter
within subjects
if you have o-(standard deviation) or o-m then you are dealing with a ____
z test
H1:Md>/0
> greater than sign means one tailed test: increase
19. A researcher conducts two t tests. Test 1 is a one-tailed test with a smaller sample size at a .05 level of significance. Test 2 is a one-tailed test with a larger sample size at a .05 level of significance. What do you know about the critical values for each test? A) Test 2 is associated with smaller critical values. B) Each test is associated with the same critical values. C) Test 1 is associated with smaller critical values. D) It depends; there is not enough information to answer this question.
A
24. To compute a two-independent sample 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? A) the pooled population variance B) the sample mean for both samples C) the pooled sample variance D) the sample size for both samples
A
25. A researcher runs an independent groups design and reports that the mean difference in response time to an auditory versus a visual cue is 0.83 seconds, with a pooled sample variance equal to 2.45. What is the effect size for this test using estimated Cohen's d? A) d = 0.53 B) d = 1.00 C) d = 0.34 D) d = 0.83
A
31. One difference between a repeated measures design and a matched samples design is that A) only one design involves observing the same participants in each group B) only one design eliminates between-persons variability C) only one design increases the power to observe an effect D) only one design is a type of related sample design
A
36. 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 ( ), then what is the decision at a .05 level of significance? A) Satisfaction ratings significantly differ, t(15) = 3.60. B) Satisfaction ratings significantly differ, t(14) = 3.60. C) Satisfaction ratings do not significantly differ, t(14) = 0.90. D) Satisfaction ratings do not significantly differ, t(15) = 0.90.
A
39. Each of the following is an advantage for using the related samples design, except A) it increases the variability measured in a study B) it can be more practical C) it minimizes standard error D) it increases the power of a research design
A
46. The following is a summary of a one-way between-subjects ANOVA: F(2, 37) = 3.42, p < .05, = .12. How many participants were observed in this study? A) 40 B) 12 C) 39 D) 37
A
An educational psychologist studies the effects of frequent testing on retention of course material. In one class, students (n = 38) take one quiz per week and a cumulative final exam. In the other class, students (n = 29) take one mid-term and a cumulative final exam. At the end of the semester, the educational psychologist compares the scores on the final exams (assume higher scores on the exam indicate greater retention of course material). ****If Mquizzes = 78 and Mexams = 74 (with s(M1-M2) = .76), what is the most likely the correct conclusion?**** a.The frequency of testing has an effect on retention of course material. b.The frequency of testing does not have an effect on retention of course material. c.The difference between the performances on the exams is due to sampling error. d.Cannot be determined from the information given.
A
An independent-measures study uses two samples, each with n = 12, to compare two treatments. If the results are evaluated with a t-test using a two-tailed test with α = .05, what is/are the boundary(ies) of the critical region? a.t = ±2.074 b.t = −2.074 c.t = +2.074 d.cannot be determined without the t-distribution table.
A
An independent-samples study has one sample with n = 10 and a second sample with n = 15 to compare two experimental treatments. What is the df value for the t-statistic for this study? a. 23 b. 24 c. 26 d. 27
A
23. Which of the following is an assumption for the two-independent sample t test, but not the one-sample t test? A) Random sampling B) Equal variances C) Normality D) Independence
B
44. Homogeneity of variance is an assumption for the one-way between-subjects ANOVA. What does this assumption mean? A) that one observation has no effect on the likelihood of another observation B) that the variance is equal in each population from which samples are selected C) that the population being sampled from is normally distributed D) that participants are randomly selected to participate in a sample
B
45. Post hoc tests are computed A) to determine if groups means differ, even for tests in which the decision is to retain the null hypothesis. B) Following a significant ANOVA test to make pairwise comparisons. C) Prior to conducting a hypothesis test. D) To determine which set of degrees of freedom can be attributed to the variability between-groups.
B
An educational psychologist studies the effects of frequent testing on retention of course material. In one class, students (n = 38) take one quiz per week and a cumulative final exam. In the other class, students (n = 29) take one mid-term and a cumulative final exam. At the end of the semester, the educational psychologist compares the scores on the final exams (assume higher scores on the exam indicate greater retention of course material). ******Which of the following is true of this study?***** a.It uses a single-sample t-test. b.It uses an independent-sample t-test. c.It uses a repeated-measures t-test. d.It uses a z-test.
B
10. 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? A) Mean scores were significant by 0.88 points in the population. B) The effect observed in the population was significant. C) Mean scores shifted 0.88 standard deviations in the population. D) Mean scores were significant by 0.88 points in the sample.
C
22. The mean crying time of infants during naptime at a local preschool is 12 minutes (that's the population mean). The school implements a new naptime routine in a sample of 25 infants and records an average crying time of 8±4.6 (M±SD) minutes. Calculate t. A) 4.35 B) 0.92 C) -4.35 D) -0.92
C
27. A researcher has participants rate the likability of a sexually promiscuous person described in a vignette as being male (n = 20) or female (n = 12). The mean likability rating in each group was 4.0. If the null hypothesis is that there is no difference in likability ratings, then do likability ratings differ at a .05 level of significance? A) No, this result is not significant, t(30) = 1.00. B) Yes, this result is significant, p < .05. C) No, this result is not significant, t(30) = 0. D) There is not enough information to answer this question, because the variance in each sample is not given.
C
28. A researcher reports a significant mean difference in a given population. If she computes both eta-squared and omega-squared to measure the effect size, then which estimate will be the most conservative? A) It depends on the value of the t statistic. B) eta-squared C) omega-squared D) It depends on the sample size.
C
35. A researcher selects a sample of 36 dog owners and measures their responsiveness to two types of pictures: one depicting the humane treatment of dogs and one depicting the inhumane treatment of dogs. The researcher finds that responsiveness significantly differed, t = 3.243. Use eta-squared to compute the proportion of variance for this result. A) = 0.25 B) = 0.21 C) = 0.23 D) There is not enough information to answer this question.
C
38. Using APA format, which value is typically given in parentheses when reporting the results for a t test? A) The estimate for standard error. B) The level of significance. C) The degrees of freedom. D) The value of the test statistic.
C
47. A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the total df? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122 A) 45 B) 8 C) 49 D) 43
C
48. A researcher computes some of the values in this F table (below) for a one-way between-subjects ANOVA. What is the MSBG ? Source of variation SS df MS F Between groups 32 4 Within groups (error) 90 45 Total 122 A) 2 B) 0.125 C) 8 D) 0.50
C
5. The probability of committing a Type I error is stated by ________; the probability for committing a Type II error is stated by ________. A) the power; the power B) beta; alpha C) alpha; beta D) a p value; a p value
C
6. Which of the following statements regarding the null hypothesis is true? A) A decision in hypothesis testing is made about the alternative hypothesis, not the null hypothesis. B) The null hypothesis is the only hypothesis stated in hypothesis testing. C) The null hypothesis always makes statements about a population parameter. D) all of the above
C
7. The one-sample z test is a hypothesis test used to test hypotheses A) concerning at least one population B) concerning the variance in a population C) concerning a single population with a known variance D) all of the above
C
A developmental psychologist is interested in determining whether a behavioral training program is effective in reducing the disruptive behavior of children in a 3rd grade class. He measures the level of disruptive behavior at the start of the school year, implements the training program, and measures the level of disruptive behavior at the end of the school year. Which test is appropriate for this type of research question? a.A single-sample t-test, because the researcher is using only one group of children. b.An independent-sample t-test, because the researcher is comparing two measurements. c.A repeated-measures t-test, because the researcher is measuring the same group at two times. d.Any of these tests is appropriate.
C
20. Which of the following is an assumption for computing any type of independent sample t test? A) Data were obtained from a sample that was selected using a random sampling procedure. B) The probabilities of each measured outcome in a study are independent. C) Data in the population being sampled are normally distributed. D) all of the above
D
32. The test statistic for a related samples t test makes tests concerning a single sample of A) participant scores B) raw scores C) original data D) difference scores
D
estimated standard error in the single sample t-test
Recall that σM is the standard error. When estimating it with sM, it's called the estimated standard error. Compute Sm=(square root)s2/n=s/(square root)n
estimated standard error of the mean
an estimate of the standard deviation of the sampling distribution
if you have M1-M2(denominator) or are provided with M for one example & M for a diff. group, then you are dealing with a ____
independent samples t-test
Leptokurtic
normal curves that are tall and thin, with only a few scores in the middle of the distribution having a high frequency
H0:Md=/0
null hypothesis; mean of the differences scores is /0; no difference from pre to post.
correlation
relationship with 2 factors that are defined by both ration and interval with no criterion and not defined
pretest -> Independent variable -> post test
repeated measures
if you have D &/or Md or are provided values for Ds of Md then you are dealing with a ____
repeated measures t-test
words to describe a repeated measures test:
same sample twice, before, after, measured time, pre, post
related samples design
samples in which the participants are observed in more than one treatment or matched on common characteristics
family of t distributions
serve as the comparison distributions we use to determine the critical level (CL) and critical region (CR) in the HT using t. (Recall that the sampling distribution was the comparison distribution we used with the z-test.)
positive/negative 1
strong
main effect
the differences in means occurring within each IV (ex. 2 factor or two IV--> each factor have 2 levels--> main effect for first Iv would be the difference (if any) between the mean of the levels isolated from the other IV and its other 2 levels)
Cohen's d measures
the size of the treatment effect
H0 is either true or false
true: outcome of Sampling Error false: outcome is not due to Sampling Error
t statistic
used to test hypotheses about an unknown population mean, u, when the value of σ is unknown. The formula for the t-statistic has the same structure as the z-score formula, except that the t statistic uses the estimated standard error in the denominator.
individual differences
variations among people in their thinking, emotion, personality, and behavior
if you have M-u(numerator) or are provided with values for M &/or u, the test must be either a _______ or ________?
z test, single sample t-test
30. A type of related samples design in which participants are observed more than once is called a A) repeated measures design B) matched pairs design C) matched samples design D) both B and C
A
18. A researcher selects a sample of 32 participants who are assigned to participate in a study with one group. What are the degrees of freedom for this test? A) 30 B) 31 C) 32 D) There is not enough information to answer this question.
B
26. Which measure of effect size is most commonly reported with a t test? A) omega-squared B) Cohen's d C) eta-squared D) t statistic
B
1. What is the typical level of significance for a hypothesis test in behavioral research? A) .001 B) .50 C) .10 D) .05
D
note that Smd(denominator) matches ___
Md(numerator)
r squared = .3
moderate
H1 < (less) you can expect
smaller value for t
estimated standard error in the independent samples t test
two estimated standard errors, one for the treatment condition (sM1) and one for the control condition (sM2). To arrive at a single value for estimated standard, we must pool (or mathematically combine) the variances from the two conditions.
if you have CL = +- then it is
two tailed meaning the CR is split between two tails
sampling error in ms between
type 2
order effects
occur when the order in which the participants experience conditions in an experiment affects the results of the study
if your H1 is > or < then it is
one tailed
2. Based on the effect size conventions, d = 0.60 is a A) large effect size B) small effect size C) medium effect size
C
what is the comparison distribution for t-statistic
family of t-distributions
Using T distribution table
find the CL that defines the CR. To do this, determine df for the test and whether the test is a one-tailed test or a two-tailed test. Then find the CL in the table that corresponds to these two components.
n^2
new step 5 in HT (other steps = same) in process of trying to computing f, n^2 computes effect size ssbetween/ sstotal