I am having trouble understanding the critical value and margin error. I am being timed if you can please get back to me soon. thank you!

1) In a simple random survey of 89 teachers who taught college statistics, 73 said that it was the most satisfying, most enjoyable course they had ever taught. In order to construct a 98% confidence interval estimate of the proportion of all community college statistics teachers who feel this way, let's following the steps: a) What is the critical value? b) What is the margin of error? c) Construct a 98% confidence interval. d) Interpret the above confidence interval. (You must follow the format from the example of instructor's video. Other way of interpretation will result in little credit or no credit.)2) To determine the mean cost of groceries in a certain city, an identical grocery basket of food is purchased at each store in a random sample of ten stores. If the average cost is $47.52 with a standard deviation of $1.59. To find a 98% confidence interval estimate for the cost of these groceries in the city. (Assume that the population is normally distributed), let's complete the following steps: a) What is the critical value? b) What is the margin of error? c) Construct a 98% confidence interval. d) Interpret the above confidence interval. (You must follow the format from the example of instructor's video. Other way of interpretation will result in little credit or no credit.)3) The values listed below are waiting times (in minutes) of customers ate a certain bank, where customers enter a single waiting line that feeds three teller windows: 6.5 6.6 6.7 6.8 7.1 7.3 7.4 7.7 7.7 7.7 To construct a 95% confidence interval for the population standard deviation, we will answer the following questions: (Assume that the population is normally distributed). a) What is the critical values (There are two of them)? b) Construct a 98% confidence interval. c) Interpret the above confidence interval. (You must follow the format from the example of instructor's video. Other way of interpretation will result in little credit or no credit.)