STATS

The results of an independent measures research study are reported as "t(22)=2.12, p<.05, two tails" for this study what t values formed the boundaries for the critical region

+- 2.074

An independent measures study comparing two treatment conditions produces a t statistic with df=18 if the two samples are the same size, how many participants were in each sample.

10 20-2=18 10+10=20 (original population)

A repeated-measures study and an independent-measures study both produced at statistic with df=10. How many individuals participated in each study?

11 for repeated-measures and 12 for independent-measures

An independent-measures study has one sample with n= 6 and a second sample with n= 8 to compare two experimental treatments. What is the df value for the t statistic for this study?

12 (8-1)+(6-1)=12

A researcher conducts a hyp test using a sample of n=20 from an unknown pop what is the df value for the t statistic

19 20-1

A sample of n=100, score is selected from a population with u=80 with o*=20 on average how much error is expected between the sample mean and population mean?

2 o*m= 20/√100=2

If an independent measure design is being used to compare two treatment conditions, then how many different groups of participants would be needed and how many scored would there be for each?

2 groups 1 score

An independent-measures research study with n= 5 participants in each treatment produces sample variances of 8 and 10, and a 2-point difference between the two treatment means. Given this information, what is the value of Cohen's d?

2/3 Md=2; SD= √9 because Var. mean is average when both n are equal

Using an independent-measures t, the 90% confidence interval for the difference between two population means ranges from 19 to 23. Based on this confidence interval, how big is the difference between the two sample means?

21 points 19 20 21 22 23 2 points apart from each

What is the pooled variance for the following two samples? Sample 1: n = 8 and SS = 168 Sample 2: n= 6 and SS = 120

24 S^2= 168/(8-1)= 24 s^2=120/(6-1)=24

An independent measure study uses n=15 participants in each group to compare two treatment conditions. What is the DF value for the t statistics for this study

28 15-1 15-1 14+14=28

Two samples both with n=5 scores, have a pooled variance of 40. What is the estimated standard error for the sample mean difference?

4 √(40/5+40/5)=√16=4

For a population with U=80, o*=20, the distribution of sample means based on n=16 will have an expected value of ______ and a standard error of _____

80;5 u=80 o*m= o*/√n = 20/√16 = 5

Which set of characteristics will produce the smallest value for the estimated standard error?

A large sample size and a small sample variance

A researcher plans to conduct a research study comparing two treatment conditions with a total of 20 participants. Which of following designs would produce 20 scores in each treatment

A repeated measure design

Which combination of factors would definitely increase the width of a confidence interval?

Increase the sample mean and increase the percentage of confidence.

Which of the following will not increase the width of a confidence interval

Increase the sample mean from Md=2 to Md=4

What is the standard error of M

It is the standard deviation of the distribution of sample means

Which of the following describes what a confidence interval does?

It uses a sample mean to estimate the corresponding population mean

One sample has n=10 scores and a variance of s^2=20 and a second sample has n= 15 scores and a variance of s^2=30 what can you conclude about pooled variance for these two samples?

It will be closer to 30 than 20

If the sample size is held constant, which of the following will produce the widest 90% confidence interval for the population mean difference for a repeated-measures study?

MD= 3 with s2 = 20 for the difference scores

which of the following accurately describes the critical region?

Outcomes with a very low probability if the null hypothesis. is true

If a hypothesis test produces a z-score in the critical region, what decision should be made?

Reject the null hypothesis

Which of the following is an accurate definition of a Type 1 error?

Rejecting a true null hypothesis

A hypothesis test involves a comparison of which two elements?

Research results from a sample and a hypothesis about a population

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

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

Which of the following is not needed to compute a t statistic?

The value of the population variance or standard deviation

Two separate samples are being used to estimate the population mean difference between two treatments conditions. Which of the following would produce the widest confidence interval

n1=n2= 10 with a pooled variance of 100

Which of the following is the correct null hypothesis for a repeated measures t test

ud=0

Which of the following is the correct null hypothesis for an independent-measures t test

μ1-μ2=0