1. Out of a sample of 150 people who walked into a fast-food restaurant, 135 said they prefer ketchup to mustard on their hamburgers. With 89% confidence, what is the confidence interval for the population mean of customers that prefer ketchup to mustard on their hamburgers? O CI = (86.09%, 93.91%) O CI = (85.20%, 94.80%) O CI = (82.61%, 95.87%) O CI = (83.69%, 96.31)   2. Out of all the students that attend Yale University, 1,982 were selected to participate in a school survey about their commute to school. 70% said that their commute to school was fine, while the others were dissatisfied with their commute. Calculate a 90% confidence interval for the proportion of students at Yale who feel their commute to school is fine the way it is. O CI = (68.76%, 71.98%) O CI = (67.35%, 72.65%) O CI = (68.31%, 71.69%) O CI = (67.98%, 72.02%)   3. Out of a sample of 500 people, 25% exercise daily. What is the confidence interval for the population mean of people that exercise daily, given a confidence level of 95%? O CI = (20.98%, 30.02%) O CI = (21.81%, 28.19%) O CI = (21.20%, 28.80%) O CI = (20.01%, 29.99%)   4. The height of pyramids in Egypt is normally distributed. A sample of 125 pyramids had a mean height of 460.7 ft and a standard deviation of 4.1 feet. With 80% confidence, what is the maximum error of estimate for the actual population mean for the height of Egyptian pyramids? O 37.04% O 47.01% O 4.21% O 94.43%

Features Features Normal distribution is characterized by two parameters, mean (µ) and standard deviation (σ). When graphed, the mean represents the center of the bell curve and the graph is perfectly symmetric about the center. The mean, median, and mode are all equal for a normal distribution. The standard deviation measures the data's spread from the center. The higher the standard deviation, the more the data is spread out and the flatter the bell curve looks. Variance is another commonly used measure of the spread of the distribution and is equal to the square of the standard deviation.