Question

A study of the number of minutes taken by top achieving students to complete a statistics assignment was carried out. A random sample of 50 top achieving students were asked how long the assignment took to complete.  The mean length of time taken by the students was found to be 75 minutes with a 95% confidence interval of (60, 90). For each of the following state if the interpretation is correct or incorrect. If incorrect expain why:

• 95% of students asked took between 60 and 90 minutes to complete the assignment. 

• We are 95% confident that top achieving students will take between 60 and 90 minutes to complete their next assignment
.
• We are 95% certain that the average time taken by the students to complete the assignment in this study was between 60 and 90 minutes. 

• If another sample of students is taken, there is a 95% chance that the average time taken will be between 60 and 90 minutes. 


Answer 1

1)95% of students asked took between 60 and 90 minutes to complete the assignment. :Incorrect

as confidence interval is about population mean and not single students

2)

We are 95% confident that top achieving students will take between 60 and 90 minutes to complete their next assignment : Correct

3) We are 95% certain that the average time taken by the students to complete the assignment in this study was between 60 and 90 minutes. 
 Incorrect ;as this will make population mean variable

4) If another sample of students is taken, there is a 95% chance that the average time taken will be between 60 and 90 minutes. 
 -Incorrect ; as confidence interval is population mean and not for range,