Question

1. Below are a list of studies that members of the Hogwarts community are doing. However, they aren’t sure what statistical test they should use. Write the name of the test for each study using the following options: Single-sample t test, Paired-sample t test, and Independent-samples t test.

1. ) McGonagall thinks that Gryffindor students perform better on their OWLS than Slytherin students, so she compares the scores of 50 students from each house.

2. )Hermione wants to compare this years scores on the OWLs exam to the scores from the last 10 years. She knows the mean score from the last 10 years but does not know the standard deviation.

c. ) Hagrid thinks that giving students hands on experience with magical creatures will increase their exam scores. He lectures on a creature and then gives a test. Then he has the students play with a creature and gives them a test. He compares the student’s scores on both tests to see if he was correct

Answer 1

(a)

Correct option:

Independent-samples t test.

Explanation: The 2 Samples (i) scores of 50 students of Gryffindor and (ii) scores of 50 students of Slytherin are independent.

(b)

Correct option:

Single-sample t test

Explanation: this years scores on the OWLs exam is compared with the mean score from the last 10 years . Since she does not know the standard deviation, t test is employed instead of Z test.

(c)

Correct option:

Paired-sample t test

Explanation: The 2 samples are not independent. The same student is measured twice: before and after the lectures.