Question:
Continue using the Cake Mix Assignment Data workbook.
Use a new Excel workbook file for this assignment.
- Copy the Assignment Data (i.e., cake mix data) to Sheet 1, cells A1:P32, of the new Excel workbook.
- Enter the following labels in cells A34:A36: Point Estimate, Lower bound of the 95% Confidence Interval, and Upper Bound of the 95% Confidence Interval. Adjust the width of column A, as needed, to accommodate labels without truncation.
- Use the cake mix data as a random sample of all grocery store cake mixes in order to estimate the population mean for sugar grams. Accordingly, calculate the point estimate of the population mean of variable "Sugar grams" by entering the appropriate formula in cell B34. Adjust cell format to round to two decimal places.
- Calculate the Lower Bound of the 95% Confidence Interval of the population mean for variable "Sugar grams" by entering the appropriate formula in cell B35 (assume the population standard deviation equals the sample standard deviation). Adjust cell format to round to two decimal places. (HINT: use the normal distribution to obtain the critical value for a 95% confidence interval.)
- Calculate the Upper Bound of the 95% Confidence Interval of the population mean for variable "Sugar grams" by entering the appropriate formula in cell B36 (assume the population standard deviation equals the sample standard deviation). Adjust cell format to round to two decimal places. (HINT: use the normal distribution to obtain the critical value for a 95% confidence interval.)
- Enter your interpretation of the 95% confidence interval in cell B37 (i.e., what are you 95% confident about?).
- Describe the hypothetical effect of sample size on the width of a confidence interval in cell B38. (Note: Wrap text and/or use adjacent cells as needed.