You must estimate the mean temperature (in degrees Fahrenheit) with the following sample temperatures: 57.9
25.4
19.8
28.3
60.7
39.4
51.1
63.4

Find the 99% confidence interval. Enter your answer as an open-interval (i. e., parentheses) accurate to two decimal places (because the sample data are reported accurate to one decimal place).

(If you could please show step by step, that would be very helpful!)

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.