CNSL 503: A GUIDE TO A+. QUESTIONS AND ANSWERS
FORMAT.LATEST UPDATE
true or false: the numerator of the t-score formula contains the estimated standard error
false! the DENOMINATOR contains the estimated standard error
the t-distribution for a __________ sample size more closely resembles the z-distribution.
- small
- large
- broad
- general
LARGE! As the sample size increases, the standard deviation decreases. Therefore, with a larger sample,
the t-distribution more closely resembles z-distribution.
if a researcher states in the alternative hypothesis that μ is less than the claimed value, what type of
test would be performed?
- two tailed
- left tailed
- right tailed
- three tailed
left-tailed
true or false: the pooled variance is used in a one sample t test
false! it is used in an INDEPENDENT samples t test
true or false: when the population standard deviation is known, researchers use the t-score.
false! researchers use the t-score when the population standard deviation is UNKNOWN
what is the number of values that may vary freely until all remaining values are determined?
- critical values
- statistical power
- effect size
- degrees of freedom
degrees of freedom
which of the following equations is used to calculate the df for a paired samples t-test?
df = n -1
df = n -2
dftotal = df1 +df2
df = (n - 1) (n - 1)
df = n - 1
, the result of a one sample t-test is found to be t = 1.14. The critical value is 2.160. What is the correct
decision regarding the null hypothesis?
Fail to reject the null hypothesis
a teacher wants to compare her students' mean math score to the mean national math score. What
type of t-test could the teacher perform?
- one sample t-test
- paired samples t-test
- independent samples t-test
- dependent samples t-test
ONE SAMPLE T-TEST! compares a single mean to a population mean.
a researcher wants to test the quality of sleep of a group of participants before and after trying a new
sleep hygiene strategy. What type of t-test could the researcher perform?
- one sample t-test
- paired sample t-test
- independent samples t-test
- dependent samples t-test
PAIRED SAMPLE T-TEST! Also known as related samples. Compares two samples /groups that are
related. This test would specifically be a repeated measures study.
a political analyst surveys participants from two political parties on their rating of local town
government to see if there is a difference between the ratings. What type of t-test could the analyst
perform?
- one sample t-test
- paired sample t-test
- independent samples t-test
- dependent samples t-test
INDEPENDENT SAMPLES T-TEST! compares the difference between two samples or groups of subjects
who are completely independent of one another. Members of one group have no relation to second
group and a member can't be in both groups.
in an independent samples study, the sample mean of one group is found to be x̄ (1) = 36.12 and the
sample mean of the other group is x̄ (2) = 35.41. The estimated standard error is s( x̄ 1 - x̄ 2) = 0.87.
With a critical value of 2.160, construct the 95% confidence interval.
μ1 - μ2 = (x̄ 1 - x̄ 2) +/- tcrit x S (x̄1 - x̄2)
36.12 - 35.41 +/- 2.160 x 0.87
= 0.71 +/- 1.88
[ -1.17, 2.59 ]
in a one sample study design with 50 participants, the sample standard deviation is found to be s=4.3.
Calculate the estimated standard error.
FORMAT.LATEST UPDATE
true or false: the numerator of the t-score formula contains the estimated standard error
false! the DENOMINATOR contains the estimated standard error
the t-distribution for a __________ sample size more closely resembles the z-distribution.
- small
- large
- broad
- general
LARGE! As the sample size increases, the standard deviation decreases. Therefore, with a larger sample,
the t-distribution more closely resembles z-distribution.
if a researcher states in the alternative hypothesis that μ is less than the claimed value, what type of
test would be performed?
- two tailed
- left tailed
- right tailed
- three tailed
left-tailed
true or false: the pooled variance is used in a one sample t test
false! it is used in an INDEPENDENT samples t test
true or false: when the population standard deviation is known, researchers use the t-score.
false! researchers use the t-score when the population standard deviation is UNKNOWN
what is the number of values that may vary freely until all remaining values are determined?
- critical values
- statistical power
- effect size
- degrees of freedom
degrees of freedom
which of the following equations is used to calculate the df for a paired samples t-test?
df = n -1
df = n -2
dftotal = df1 +df2
df = (n - 1) (n - 1)
df = n - 1
, the result of a one sample t-test is found to be t = 1.14. The critical value is 2.160. What is the correct
decision regarding the null hypothesis?
Fail to reject the null hypothesis
a teacher wants to compare her students' mean math score to the mean national math score. What
type of t-test could the teacher perform?
- one sample t-test
- paired samples t-test
- independent samples t-test
- dependent samples t-test
ONE SAMPLE T-TEST! compares a single mean to a population mean.
a researcher wants to test the quality of sleep of a group of participants before and after trying a new
sleep hygiene strategy. What type of t-test could the researcher perform?
- one sample t-test
- paired sample t-test
- independent samples t-test
- dependent samples t-test
PAIRED SAMPLE T-TEST! Also known as related samples. Compares two samples /groups that are
related. This test would specifically be a repeated measures study.
a political analyst surveys participants from two political parties on their rating of local town
government to see if there is a difference between the ratings. What type of t-test could the analyst
perform?
- one sample t-test
- paired sample t-test
- independent samples t-test
- dependent samples t-test
INDEPENDENT SAMPLES T-TEST! compares the difference between two samples or groups of subjects
who are completely independent of one another. Members of one group have no relation to second
group and a member can't be in both groups.
in an independent samples study, the sample mean of one group is found to be x̄ (1) = 36.12 and the
sample mean of the other group is x̄ (2) = 35.41. The estimated standard error is s( x̄ 1 - x̄ 2) = 0.87.
With a critical value of 2.160, construct the 95% confidence interval.
μ1 - μ2 = (x̄ 1 - x̄ 2) +/- tcrit x S (x̄1 - x̄2)
36.12 - 35.41 +/- 2.160 x 0.87
= 0.71 +/- 1.88
[ -1.17, 2.59 ]
in a one sample study design with 50 participants, the sample standard deviation is found to be s=4.3.
Calculate the estimated standard error.
