QUESTION 1 t(df=14) = 3.35, one-tailed. Based on these results we _____. reject
ID: 3124932 • Letter: Q
Question
QUESTION 1
t(df=14) = 3.35, one-tailed. Based on these results we _____.
reject Ho.
fail to reject Ho.
accept Ho.
reject Ha.
2 points
QUESTION 2
When determining the pooled population variance estimate in a t test for independent means:
the variance of at least one of the original populations must be known (as opposed to estimated), but the other can be estimated from sample scores
the variance of BOTH of the original populations must be known, as opposed to estimated
the estimates based on each of the samples are averaged in such a way as to give more influence to the estimate based on more participants
the scores from both samples are combined to form a single sample, and the estimated variance is figured in the usual way, but using this combined sample
2 points
QUESTION 3
Imagine that you conducted an independent-groups t test with 15 participants in each group. For a one-tailed test, the tcv at p = .05 would be:
+ OR - 1.701.
+ OR - 2.074.
+/- 1.711.
+/- 2.064.
2 points
QUESTION 4
The alternative hypothesis for a one-tailed independent-groups t test states that:
Ho: µ1 = µ2.
Ho: µ1 < µ2.
Ha: µ1 µ2.
Ha: µ1 > µ2 or Ha: µ1 < µ2.
2 points
QUESTION 5
Consider a study in which the population variance estimate based on an experimental group of 10 participants is 70, and the population variance estimate based on a control group of 20 participants is 50. Compute the pooled estimate of population variance.
48.6
56.4
61.3
65.4
2 points
QUESTION 6
Which of the following is an example of a situation in which you could conduct a t test for independent means?
A comparison of the SAT scores of a group of 10 students who completed a special SAT preparation course compared to how people do on the SAT in general
A comparison of scores of participants in a memory study in which one group learns the words in alphabetical order and another group learns the words in order of word length
A comparison of participants’ scores on a skills test before and after attending a training session for improving the skill
None of the above would be suitable for a t test for independent means
2 points
QUESTION 7
In a t test for independent means, the weighted average of the estimates of the population variance from two samples is known as the:
estimate of sample standard deviation
primed estimate of population standard deviation
pooled estimate of population variance
pooled estimate of degrees of freedom
2 points
QUESTION 8
You conduct a t test for independent means and reject the null hypothesis. This means that:
the samples were from populations that were actually dependent rather than independent
the variance of one sample is so much larger than the variance of the other sample that you decide that the variances of the parent populations must not have been the same
the mean of one sample is so far from the mean of the other sample that you decide the samples must come from populations with different means
the mean of one sample is statistically the same as the mean of the other sample, so they probably come from populations with equal means
2 points
QUESTION 9
For a two-tailed t test for independent means, tcv = 3.35 and tobt = -3.55. Based on these results we _____.
reject Ho.
fail to reject Ho.
accept Ho.
reject Ha.
2 points
QUESTION 10
Which of the following t test results has the greatest chance of statistical significance?
t(28) = 1.70
t(14) = 1.70
t(18) = 1.70
t(10) = 1.70
2 points
QUESTION 11
The null hypothesis for a one-tailed independent-groups t test states that:
Ho: µ1 µ2, or Ho: µ1 µ2
Ho: µ1 = µ2.
Ha: µ;1 = µ2.
Ha: µ1 µ2.
2 points
QUESTION 12
Imagine that you conducted an independent-groups t test with 7 participants in each group. For a two-tailed test, the tcv at p = .05 would be:
+ OR - 1.717.
+ OR -2.074.
+/- 1.711.
+/- 2.179.
2 points
QUESTION 13
Based on the following results, which would be the correct use of the formula t = (M1–M2) /SDifference?
Sample 1: Mean = 60; Variance of the sampling distribution = 2
Sample 2: Mean = 50; Variance of the sampling distribution= 7
t = (7–2) / 50 + 60
t = (60–50) / 4 + 49
t = 60–50 / 3
t = 60–50 / 9
2 points
QUESTION 14
t(df=20) = 1.99, two-tailed. Based on these results we _____.
reject Ho.
fail to reject Ho.
accept Ha.
fail to reject Ha.
2 points
QUESTION 15
All of the following are true for both the t test for independent means AND the t test for dependent means, EXCEPT:
population variances are estimated from the information in the sample of scores actually studied
pretest–posttest experimental designs are common
the population means are unknown
the sample scores (in some form) are eventually compared to a t distribution
2 points
QUESTION 16
An independent-groups t test:
compares sample means for two related groups.
compares sample means for two unrelated groups.
compares standard deviations for two unrelated group.
compares sample means for three or more unrelated groups.
2 points
QUESTION 17
The comparison distribution for a t test for independent means is a t distribution (as opposed to a normal curve) because:
tables are not available for the normal curve
the population variance is estimated
Z distributions were not used at the time the t test for independent means was invented
there are more degrees of freedom for a single sample than for when you use two samples
2 points
QUESTION 18
Each of the following is part of conducting a t test for independent means, EXCEPT:
difference scores are found for each participant
the population variances are estimated
a comparison is made against a t distribution
the variance of the distribution of differences between means is figured
2 points
QUESTION 19
If an independent-groups t test has 10 participants in each group, then the degrees of freedom are:
9.
10.
20.
18.
2 points
QUESTION 20
The comparison distribution for a t test for independent means is a:
distribution of differences between means
Z distribution (i.e., a normal curve)
distribution of difference scores
distribution of proportional variance scores
2 points
QUESTION 21
When conducting a t test for independent means, once the variances are known for each of the distributions of means, the variances can be added together to give the:
pooled estimate of the population variance
variance of the distribution of differences between means
t score
power of the study
2 points
QUESTION 22
If an independent-groups t test has 7 participants in each group, then the degrees of freedom are:
7.
14.
6.
12.
2 points
QUESTION 23
Which of the following is the best way to reduce the variances in the sampling distribution when conducting a t test for independent means?
Increase the size of the samples
Raise the study’s level of significance
Use the true population variance
Treat the two samples as one sample
2 points
QUESTION 24
As sample variance _____, the value of the t test _____.
increases; increases
decreases; decreases
increases; decreases
increases; stays the same
2 points
QUESTION 25
When using a t table, the degrees of freedom you should use for a t test for independent means is the:
degrees of freedom for Sample 1 divided by the total degrees of freedom for both samples
average of the degrees of freedom for the two samples
sum of the two sample sizes, minus one
sum of the two samples’ degrees of freedom
reject Ho.
fail to reject Ho.
accept Ho.
reject Ha.
Explanation / Answer
The answers are given below :
1) Reject H0.
2) the estimates based on each of the samples are averaged in such a way as to give more influence to the estimate based on more participants.
3) + OR - 2.074.
4)Ha: µ1 > µ2 or Ha: µ1 < µ2.
5) 56.4
6) A comparison of scores of participants in a memory study in which one group learns the words in alphabetical order and another group learns the words in order of word length
7) pooled estimate of population variance
8) the mean of one sample is so far from the mean of the other sample that you decide the samples must come from populations with different means
9) reject Ho
10) t(10) = 1.70
11) Ho: µ1 µ2, or Ho: µ1 µ2
12) +/- 2.179.
13) t = 60–50 / 9
14) fail to reject Ho
15)pretest–posttest experimental designs are common
16) compares sample means for two unrelated groups.
17) the population variance is estimated
18) difference scores are found for each participant
19) 18.
20) Z distribution (i.e., a normal curve)
21) pooled estimate of the population variance
22) 12
23) Increase the size of the samples
24) increases; decreases
25) sum of the two samples’ degrees of freedom
3)
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.