Question

You have purchased an inexpensive voltage supply that has a nominal supply value of 5 V. You wish to determine if the supply actually provides this voltage. So you use a multi-meter to measure the supply voltage under different load conditions. You generate the data

Measurement (V)

4.97

4.95

4.98

4.99

5.01

5.00

4.98

5.00

Do a statistical analysis on this data to determine if the supply voltage is actually 5 V. What does your analysis indicate?

The supply voltage is 5 V.

The supply voltage is not 5V.

What is the P value associated with your decision

Answer 1

Null hypothesis  

          
              
Alternative hypothesis     

       
              
We have for given sample,              
Population mean for given sample=5
Sample mean=4.985      
Sample standard deviation s=0.0193  
Sample size =n=8      
              
Degree of freedom = n-1 =7  
              
              
              
t test statistic formula is              


=-2.198      

P value =0.0639........................by using Excel command TDIST(-2.198,7,2)