QUESTION 20 Opal wonders how quickly professional typists can type. She finds a SRS of 40 typists who have a mean typing speed of 70 wpm (words per minute). The sample has a standard deviation of 15 wpm. Help Opal construct a 98% confidence interval for the population mean typing speed. Round interim values to the nearest thousandth and your final answers to the nearest whole amount. Identify the problem type & critical value. Problem Type Critical Value Determine the standard error. Work/Explain Answer Determine the margin of error. Work/Explain Answer State the confidence interval. Answer SUS Work/Explain