Exam 1

1. Metainformation

   Tag	Value
   file	Inferential_Statistics_vufgb-confidenceintervals-024-en_vufgb-confidenceintervals-024-en
   name	vufgb-confidenceintervals-024-en
   section	Inferential Statistics/Confidence Intervals
   type	schoice
   solution	FALSE, TRUE, FALSE, FALSE
   Type	English
   Program
   Language	Dutch
   Level	Statistical Thinking

   Question

   The mean in a sample of 25 persons is 15, the variance is 9.

   Calculate the 95% confidence interval for the population mean.

   
   
   1. FALSE: 13.82 ; 16.18
   2. TRUE: 13.76 ; 16.24
   3. FALSE: 11.28 ; 18.72
   4. FALSE: 14.75 ; 15.25
   
   

   Solution

   $95 \% \; CI: \; mean \pm t._{025} \times se$

   So, firstly you have to find the corresponding t-value and calculate the standard error.

   t-value at $df = n-1 = 25-1 = 24: \; 2.064$

   $se = \frac{s}{\sqrt{n}} = \frac{3}{5} = 0.6$

   When you fill this in, you get: $15 \pm 2.064 \times 0.6$, which is $13.76 \; ; \; 16.24$.

   
   
   1. Incorrect
   2. Correct
   3. Incorrect
   4. Incorrect