Exam 1

1. Metainformation

   Tag	Value
   file	Inferential_Statistics_vufsw-confidence_intervals-1260-en_vufsw-confidence_intervals-1260-en
   name	vufsw-confidence intervals-1260-en
   section	inferential statistics/confidence intervals
   type	schoice
   solution	TRUE, FALSE, FALSE, FALSE
   Type	conceptual
   Program	NA
   Language	English
   Level	statistical literacy

   Question

   The effectiveness of a new diet is examined. It is suspected that people lose weight when they use the diet. For 150 respondents the weight is measured in a pre-test (before they start the diet) and in a post-test (two weeks after they have started the diet). A 95% confidence interval is calculated for the mean difference in weight, Mean _{before measurement} - Mean _{after measurement}. This interval appears to be (1.6, 2.8). What can we conclude?

   
   
   1. TRUE: In at least 95% of all possible samples, we will find an average weight loss between 1.6 and 2.8.
   2. FALSE: In at least 95% of all possible samples, we will find an average increase in weight between 1.6 and 2.8.
   3. FALSE: The values of the interval are not in the critical area, so we cannot reject the null hypothesis.
   4. FALSE: The values of the interval are in the critical area, so we cannot reject the null hypothesis.
   
   

   Solution

   Based on this sample, we are 95% sure that the diet leads to a significant decrease in weight. Because the 0 is not in the CI

   
   
   1. True
   2. False
   3. False
   4. False