4/5/2018 Two Independent Samples Checkpoint | Acrobatiq
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MODULE INFERENCE FOR RELATIONSHIPS
TWO INDEPENDENT SAMPLES CHECKPOINT
Step 1 of 1
Question 1 of 5 Points: 10 out of 10
A teacher is experimenting with a new computer-based instruction and conducts a study to test its effectiveness. In which situation could the teacher
use the two-sample t-test for comparing two population means?
The teacher gives each student in the class a pretest. Then she teaches a lesson using a computer program. Afterwards, she gives each
student a post-test. The teacher wants to compare test scores for each student to see whether the data will show an improvement.
The teacher randomly divides the class into two groups. One of the groups receives computer-based instruction and the other group
receives traditional instruction without computers. After instruction, each student takes a test and the teacher wants to compare the
test scores of the two groups.
The teacher uses a combination of traditional methods and computer-based instruction. She asks students which they liked better. She
wants to determine if the majority prefer the computer-based instruction.
Good Job! Since students were randomized to two different groups the data obtained from this study should be analyzed
using the two (independent) samples t-test.
Question 2 of 5 Points: 10 out of 10
College Students and Drinking Habits: A public health official is studying differences in drinking habits among students at two different universities.
Th ll d l f d i d d l f h f h i ii d k
https://straighterline.acrobatiq.com/courseware/summative-assessment/sl_stats_v1/_u5_m2_two_indep_samples_checkpoint1/5ac6391f00000935c7790139 h d h l h li d i k h 1/5
, 4/5/2018 Two Independent Samples Checkpoint | Acrobatiq
They collect a random sample of students independently from each of the two universities and ask each student how many alcoholic drinks they
consumed in the previous week.
The official conducts a two-sample t-test to determine whether these data provide significant evidence that students at University 1 drink more than
students at University 2. The test statistic is t = 2.64 with a P-value 0.005.
Which of the following is an appropriate conclusion?
The samples provide significant evidence that students at University 1 drink more than students at University 2.
The samples do not provide statistically significant evidence.
We can not use the t-test in this case because the variables (number of drinks) are likely skewed to the right at each university.
Good job! A P-value this small indicates statistically significant results.
Question 3 of 5 Points: 10 out of 10
In a study of the impact of smoking on birth weight, researchers analyze birth weights (in grams) for babies born to 189 women who gave birth in
1989 at a hospital in Massachusetts. In the group, 74 of the women were categorized as “smokers” and 115 as “non-smokers.” The difference in the
two sample mean birth weights (non-smokers minus smokers) is 281.7 grams and the 95% confidence interval is (76.5, 486.9)
Which gives the best interpretation of what we can conclude about the impact of smoking on birth weight?
We are 95% confident that on average, smoking causes lower birth weights of between 76.5 grams to 486.9 grams.
There is a 95% chance that if a woman smokes during pregnancy her baby will weigh between 76.5 grams to 486.9 grams less than if she
did not smoke.
https://straighterline.acrobatiq.com/courseware/summative-assessment/sl_stats_v1/_u5_m2_two_indep_samples_checkpoint1/5ac6391f00000935c7790139 2/5
CALL: (855) 836-4203 LIVE CHAT HELP CENTER MyLine Log Out
Tutoring (/lti_navigation_launch/sl_stats_v1/58eeb3630837637d7a50017a)
BACK TO COURSE (/COURSEWARE/PAGE/SL_STATS_V1/_U5_M02_TWO_INDEPENDENT_SAMPLES7)
MODULE INFERENCE FOR RELATIONSHIPS
TWO INDEPENDENT SAMPLES CHECKPOINT
Step 1 of 1
Question 1 of 5 Points: 10 out of 10
A teacher is experimenting with a new computer-based instruction and conducts a study to test its effectiveness. In which situation could the teacher
use the two-sample t-test for comparing two population means?
The teacher gives each student in the class a pretest. Then she teaches a lesson using a computer program. Afterwards, she gives each
student a post-test. The teacher wants to compare test scores for each student to see whether the data will show an improvement.
The teacher randomly divides the class into two groups. One of the groups receives computer-based instruction and the other group
receives traditional instruction without computers. After instruction, each student takes a test and the teacher wants to compare the
test scores of the two groups.
The teacher uses a combination of traditional methods and computer-based instruction. She asks students which they liked better. She
wants to determine if the majority prefer the computer-based instruction.
Good Job! Since students were randomized to two different groups the data obtained from this study should be analyzed
using the two (independent) samples t-test.
Question 2 of 5 Points: 10 out of 10
College Students and Drinking Habits: A public health official is studying differences in drinking habits among students at two different universities.
Th ll d l f d i d d l f h f h i ii d k
https://straighterline.acrobatiq.com/courseware/summative-assessment/sl_stats_v1/_u5_m2_two_indep_samples_checkpoint1/5ac6391f00000935c7790139 h d h l h li d i k h 1/5
, 4/5/2018 Two Independent Samples Checkpoint | Acrobatiq
They collect a random sample of students independently from each of the two universities and ask each student how many alcoholic drinks they
consumed in the previous week.
The official conducts a two-sample t-test to determine whether these data provide significant evidence that students at University 1 drink more than
students at University 2. The test statistic is t = 2.64 with a P-value 0.005.
Which of the following is an appropriate conclusion?
The samples provide significant evidence that students at University 1 drink more than students at University 2.
The samples do not provide statistically significant evidence.
We can not use the t-test in this case because the variables (number of drinks) are likely skewed to the right at each university.
Good job! A P-value this small indicates statistically significant results.
Question 3 of 5 Points: 10 out of 10
In a study of the impact of smoking on birth weight, researchers analyze birth weights (in grams) for babies born to 189 women who gave birth in
1989 at a hospital in Massachusetts. In the group, 74 of the women were categorized as “smokers” and 115 as “non-smokers.” The difference in the
two sample mean birth weights (non-smokers minus smokers) is 281.7 grams and the 95% confidence interval is (76.5, 486.9)
Which gives the best interpretation of what we can conclude about the impact of smoking on birth weight?
We are 95% confident that on average, smoking causes lower birth weights of between 76.5 grams to 486.9 grams.
There is a 95% chance that if a woman smokes during pregnancy her baby will weigh between 76.5 grams to 486.9 grams less than if she
did not smoke.
https://straighterline.acrobatiq.com/courseware/summative-assessment/sl_stats_v1/_u5_m2_two_indep_samples_checkpoint1/5ac6391f00000935c7790139 2/5
