=zyBooks My library > MAT 240: Applied Statistics home > 7.2: Confidence intervals for population proportions zyBooks catalog ? Help/FAQ & Cynthia Raybeck CHALLENGE ACTIVITY 7.2.3: Excel: Confidence intervals for a proportion. Click this link to download the spreadsheet for use in this activity. Critical values for quick reference during this activity. Confidence level Critical value 0.90 2* = 1.645 0.95 2* = 1.960 0.99 2* = 2.576 387788.2537744.qx3zqy7 Jump to level 1 The manager of a bookstore with a coffee shop wants to know the proportion of customers that come into the store because of the coffee shop. A random sample of 75 customers was polled. Use Sheet 3 of the Excel file linked above to calculate p and the 95% confidence interval. p = Ex: 1.234 Upper bound for 95% confidence interval = Ex: 1.234 Lower bound for 95% confidence interval = The manager can say with 95% confidence that the true population proportion of the customers that come into the store because of the coffee shop is in the interval [ Ex: 1.234 , 3 Check Next Type here to search O 2 x O :06 PM 77.F Sunny 4/7/2022 E