s/rm

a sample is selected from a population with u=46, and a treatment is administered to the sample. After treatment, the sample mean is M=48 with a sample variance of s^2=16. Based on this information, what is the value of Cohen's d?

d= 0.50

under what circumstances can a very small treatment effect be statistically significant?

if the sample size is large and the sample variance is small

a sample of n=16 scores produces a t-stat of t=+2.00. If the sample is used to measure effect size with r^2, which value will be obtained for r^2?

r^2= 0.21

a sample of n=4 scores has a variance of s^2=64. What is the estimated standard error for the sample mean?

sM=4

what is the sample variance and estimated standard error for a sample of n=9 scores with ss= 72

s^2=9 and sM=1

if a treatment is expected to increase scores on a variable for which the mean is expected to be =100m what is the null hypothesis?

uTreatment<100

all else constant, which combination of factors would increase the width of a confidence interval most?

a smaller sample size and a larger confidence intervals

a hypothesis test produces a t-stat of t= +2.19. If the researcher is conducting a two-tailed test with a=.05, how large does the sample have to be in order to reject the null hypothesis?

at least n=13

a researcher conducts a hypothesis test using a sample of n=20 with M=34 and s^2=36 from an unknown population. What is the df value for the t-stat

df=19

if n=63 for a two-tailed hypothesis test in which a t-test should be utilized, which df value should be referenced when using the abridged t-distribution table in the textbook in order to set the critical t values for the hypothesis test

df=60

which bit of information is not obtainable from the results of a t-test written up in a statistical report?

each of these bits of information is obtainable from the results of a t-test written up in a statistical report

when n is small (less than 30), how does the shape of the t-distribution compare to the normal distribution?

it is flatter and more spread out than the normal distribution

how much does sample variance influence the estimated standard error and measures of effect size such as r^2 and Cohen's d?

larger sample variance increase the estimated standard error but decreases measures of effect size

which of the following samples will have the smallest value for the estimated standard error?

n=16 with s^2=64

a sample with a mean of M=40 and a variance of s^2=12 has an estimated standard error of 2 points. How many scores are in the sample

n=3

which situation below violates an assumption for conducting hypothesis test using the t-stat?

non of these situations violates an assumption for conducting hypothesis tests using the t-stat

which of the following results from a hypothesis test involving the computation of a s-stat is structured correctly based on standards for presenting hypothesis tests in scientific reports?

t(19) = 2.30, p<.05, r^2 =0.42

with a=.05, the two-tailed critical region for a t-test using a sample of n=20 participants would have boundaries of

t= +/- 2.093

if a treatment produces a sample mean of M=25 with s=18 among a sample of n=36, which t-stat should be obtained and which decision should be made if conducting a two-tailed hypothesis test with a=.05 and an expected mean of u=30

t= -1.67 and fail to reject null hypothesis

assuming all other factors are held constant, if the df value for a two-tailed t-test with a= .05 were increased from df=6 to df=20, what would happen to the critical values for t?

the critical values would move closer to t=0

which of the following is consistent with what r^2 represents as a measure of effect size?

the portion of variability in a sample attributable to a treatment effect relative to the total variability in the sample

the results of a hypothesis test are reported as follows in a scientific report: t(17)= +2.76. p<.05. Based on this information, which statement is not correct?

the probability that there is a statistically significant effect is less than 5%

if a researcher is using a t-stat to test a null hypothesis about a population, what information is needed from the population to calculate the t-stat?

the researcher does not need to know any information about the population

a sample of n=25 scores produces a t-stat of t= +/- 2.052. If the researcher is conducting a two-tailed hypothesis test, which of the following is the correct statistical decision?

the researcher should fail to reject the null hypothesis with either a=.05 or a=.01

which of the following is a fundamental difference between a t-stat and a z-score

the t-stat uses the sample variance in place of the population mean