Question 1

select one answer.

10 points

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.

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.

Step-by-step explanation:

A two sample t-test is used to compared the means of two samples who were exposed to different scenarios and therefore, it helps us to see the difference between these two samples.

In this problem, the teacher is experimenting with a new computer-based instruction. To be able to use the two-sample t-test she would have to have two randomly assigned samples and expose each of these two samples to different scenarios (one would receive a traditional instruction and the other one would receive a computer instruction), and finally she would need to compare the scores in both samples.

Therefore, the correct answer would be b) 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.

*Option A is incorrect because the students are only exposed to the lesson using a computer program and therefore they aren't exposed to different scenarios.

*Option C is incorrect because although in this case the teacher uses both traditional and computer methods, there are not two different samples and she only gets the opinion of the students which is not an exact method of getting information on the effectiveness of the computer based method.

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step-by-step explanation:

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4/6 = 2/3

so it should take 3/3 hours per man. so 9 hours is the answer 3*3 =9

step-by-step explanation: