In a random sample of 40 people at a frozen yogurt shop, it was found that they ordered an average of 6.7 ounces with a standard deviation of 2 ounces. Construct a 91% confidence interval for the average number of ounces ordered from this frozen yogurt shop.

1. Which parameter are you estimating?
   Select an answer p p̂ x̄ s μ σ σ² s²
   
   
2. What is the point estimate?
   Select an answer p p̂ x̄ s μ σ σ² s² =
   
   
3. Check all of the requirements that are satisfied.
   
   • random
   • the $\displaystyle \overline{{{x}}}$ distribution is normal since $\displaystyle {n}\ge{30}$
   • the $\displaystyle \overline{{{x}}}$ distribution is normal since the $\displaystyle {x}$ distribution is normal
   • the $\displaystyle \hat{{{p}}}$ distribution is normal since $\displaystyle {n}{p}\ge{10}$ and $\displaystyle {n}{q}\ge{10}$
   
   
   
4. Find the margin of error. (You can find this without the critical value, but if prefer, you can use a critical value of $\displaystyle {t}_{{c}}={1.7386}$.)
   $\displaystyle {E}=$
   
   
5. Give the confidence interval in interval notation.
   Preview Question 6 Part 6 of 7  
   
   
6. Select the correct conclusion.
   
   • We are 91% confident that the average number of ounces ordered by the 40 people in the sample is between the two numbers found.
   • We are 91% confident that the average number of ounces ordered all of the customers at this frozen yogurt shop is between the two numbers found.
   • We are 91% confident that the proportion of ounces ordered all of the customers at this frozen yogurt shop is between the two numbers found.
   • We are 91% confident that 91% that the number of people that go to the frozen yogurt shop is between the two numbers found.