Statistics EXAM 3 QUESTIONS WITH
DETAILED VERIFIED ANSWERS (100%
CORRECT ANSWERS) / ALREADY
GRADED A+
Why do T and not Z
Under what circumstance is a T score used instead of a Z for hypothesis test ? ✔✔The T
statistic is used when POPULATION VARIANCE or STANDARD DEVIATION is unknown
-The T statistic uses the SAMPLE VARIANCE or SD in place of the unknown Population values
Why is T more Variable than Z
Why T distributions tend to be flatter and more spread out than a normal distribution ?
✔✔The sample Variance s2 in the T formula changes from one sample to another and
contributes to the variability of the T statistics.
T is ESTIMATED
REJECT H0 (direction) ✔✔p<.05
FAIL TO REJECT (direction) ✔✔p>.05
Independent Measures T ✔✔MOST variable due to Individual differences
Matched ✔✔LESS variable reduced individual difference
Repeated ✔✔LEAST variable no individual difference
, Homogeneity of Variance
Why is it important for independent measures T test ? ✔✔Variances are equal for the two
populations from which the samples are obtained
*If this is violated the T statistic can cause misleading conclusions in a hypothesis test.
How does the following influence the value of the independent-measures T statistic and
likelihood of rejecting Null hypothesis
1. Increasing the number of scores in a sample ✔✔As sample size increases the value of T
INCREASES and the likelihood of rejecting the null hypothesis (Ho) INCREASES
How does the following influence the value of the independent-measures T statistic and
likelihood of rejecting Null hypothesis
2. Increasing the variance for each sample ✔✔As variance increases the value of T
DECREASES and the likelihood of rejecting the null hypothesis (Ho) DECREASES
repeated T test or not? Explain
A researcher is comparing the amount of time spent playing video games each week for
college males versus college females. ✔✔This is an independent-measures experiment with
two separate samples
A researcher is comparing two new designs for cell phones by having a group of high school
students send a scripted text message on each model and measuring the difference in speed
for each student. ✔✔This is repeated measures - the same individuals are measured twice
A researcher is evaluating the effects of fatigue by testing people in the morning when they
are well rested and again at midnight when they have been awake 14 hours ✔✔This is
repeated measures the same individuals are measured twice.
DETAILED VERIFIED ANSWERS (100%
CORRECT ANSWERS) / ALREADY
GRADED A+
Why do T and not Z
Under what circumstance is a T score used instead of a Z for hypothesis test ? ✔✔The T
statistic is used when POPULATION VARIANCE or STANDARD DEVIATION is unknown
-The T statistic uses the SAMPLE VARIANCE or SD in place of the unknown Population values
Why is T more Variable than Z
Why T distributions tend to be flatter and more spread out than a normal distribution ?
✔✔The sample Variance s2 in the T formula changes from one sample to another and
contributes to the variability of the T statistics.
T is ESTIMATED
REJECT H0 (direction) ✔✔p<.05
FAIL TO REJECT (direction) ✔✔p>.05
Independent Measures T ✔✔MOST variable due to Individual differences
Matched ✔✔LESS variable reduced individual difference
Repeated ✔✔LEAST variable no individual difference
, Homogeneity of Variance
Why is it important for independent measures T test ? ✔✔Variances are equal for the two
populations from which the samples are obtained
*If this is violated the T statistic can cause misleading conclusions in a hypothesis test.
How does the following influence the value of the independent-measures T statistic and
likelihood of rejecting Null hypothesis
1. Increasing the number of scores in a sample ✔✔As sample size increases the value of T
INCREASES and the likelihood of rejecting the null hypothesis (Ho) INCREASES
How does the following influence the value of the independent-measures T statistic and
likelihood of rejecting Null hypothesis
2. Increasing the variance for each sample ✔✔As variance increases the value of T
DECREASES and the likelihood of rejecting the null hypothesis (Ho) DECREASES
repeated T test or not? Explain
A researcher is comparing the amount of time spent playing video games each week for
college males versus college females. ✔✔This is an independent-measures experiment with
two separate samples
A researcher is comparing two new designs for cell phones by having a group of high school
students send a scripted text message on each model and measuring the difference in speed
for each student. ✔✔This is repeated measures - the same individuals are measured twice
A researcher is evaluating the effects of fatigue by testing people in the morning when they
are well rested and again at midnight when they have been awake 14 hours ✔✔This is
repeated measures the same individuals are measured twice.
