Question

14_ The average chocolate chip cookie contains 110 calories. A random sample of 15 different brands of chocolate chip cookies found that the average amount of calories was 127 calories with a sample deviation of 6.23 calories. At .01 level of significance, test the hypothesis that the average calories for chocolate chip cookies greater than 110.

What are your null (H0) and alternative (H1) hypotheses?

What is the z or t score for step 2

What is the statistic value for step 3?

What is the decision step 4?

Answer 1

Step 1) Null hypothesis      

           
                  
Alternative hypothesis         

   

Step 2 ) We need to use here T score, Since sample size less than 30 and population standard deviation not given.

Step 3)
                  
We have for given sample,                  
Population mean for given sample=110  
Sample mean=127          
Sample standard deviation s=6.23      
Sample size =n=   15          
                  
Degree of freedom = n-1 =14      
                  

                  
t test statistic formula is

Step 4 ) P value is 0.0001.....................by using Excel command TDIST(10.57,14,1)  

P value is 0.0001 < 0.01

Therefore, we reject H0.

Conclusion: We have sufficient evidence at to say that, the average calories for chocolate chip cookies greater than 110.