Hi,
I need help please solving a confidence interval question. I posted my steps below (written and Excel paste) and the question at the very bottom. Could someone please help me with the answer? I posted my steps in the screen shot below but the quiz states I have receive .67 points of 1 correct. I'm a bit baffled as to partial credit since it's a rinse and repeat formula. Where did I do something wrong?
So 100 = stores; 140 = units aka mean; 50 is standard deviation then calculate the 99 95 68 ----> so I simply 140 +/- (2.576) (50 divided square root 100 [which is 5]) = 2.576*5 = 12.88 and then it's 140 +/- 12.88.
Question: The marketing team at Beth's Butter Works decided they preferred the traditional plastic tub packaging, but they wanted a more refined estimate of potential sales. They launched a third test at a regional level across 100 stores. These 100 stores had average daily sales of 140 units with a standard deviation of 50.
Calculate the 68% confidence intervals for the average number of units Beth's Butter Works can anticipate to sell. Enter your results in the blanks below.
I need help please solving a confidence interval question. I posted my steps below (written and Excel paste) and the question at the very bottom. Could someone please help me with the answer? I posted my steps in the screen shot below but the quiz states I have receive .67 points of 1 correct. I'm a bit baffled as to partial credit since it's a rinse and repeat formula. Where did I do something wrong?
So 100 = stores; 140 = units aka mean; 50 is standard deviation then calculate the 99 95 68 ----> so I simply 140 +/- (2.576) (50 divided square root 100 [which is 5]) = 2.576*5 = 12.88 and then it's 140 +/- 12.88.
Question: The marketing team at Beth's Butter Works decided they preferred the traditional plastic tub packaging, but they wanted a more refined estimate of potential sales. They launched a third test at a regional level across 100 stores. These 100 stores had average daily sales of 140 units with a standard deviation of 50.
Calculate the 68% confidence intervals for the average number of units Beth's Butter Works can anticipate to sell. Enter your results in the blanks below.