Question

A call center manager wants to track the number of mistakes that her staff makes on a daily basis. she gathered the following number of mistakes each day last​ week: monday​ 12, tuesday​ 20, wednesday​ 8, thursday​ 10, and friday 18. what would be the upper control limit for the c​-chart?

Answer 1

To calculate the upper control limit for a c-chart, you need to calculate the average number of mistakes per day and the standard deviation. Then, use the formula: upper control limit = average + 3 * standard deviation.

Step-by-step explanation:

To calculate the upper control limit for a c-chart, we need to first calculate the average number of mistakes per day and the standard deviation. We can then use the formula: upper control limit = average number of mistakes per day + 3 * standard deviation.

Given the number of mistakes each day last week (12, 20, 8, 10, and 18), we can calculate the average as (12 + 20 + 8 + 10 + 18) / 5 = 13.6.

Next, we calculate the sample standard deviation using the formula: standard deviation = square root of ((sum of (number of mistakes - average)^2) / (n - 1)). Plugging in the values, we get standard deviation = square root of (((12 - 13.6)^2 + (20 - 13.6)^2 + (8 - 13.6)^2 + (10 - 13.6)^2 + (18 - 13.6)^2) / (5 - 1)). Calculating this gives us a standard deviation of 4.6.

Finally, substituting the values into the formula, we get: upper control limit = 13.6 + 3 * 4.6 = 27.4.