Math check
posted by TOM95 .
While writing an article on the high cost of college education, a reporter took a random sample of the cost of new textbooks for a semester. The random variable x is the cost of one book. Her sample data can be summarized by the following. (Give your answers correct to two decimal places.)
n = 21, Óx = 3635.6, and Ó(x  x)2 = 9750.4
(a) Find the sample mean, x.
$ 173.12.
(b) Find the sample standard deviation, s.
$ 22.08 .
(c) Find the 90% confidence interval to estimate the true mean textbook cost for the semester based on this sample.
Lower Limit $
Upper Limit $
I can not get the limits to work out I have tried 4 times and I only have one more time. I have plugged information into calculator that worked on other limits but not this one.
Respond to this Question
Similar Questions

math
I did the first part how would i graph it. Problem: Business and finance. The cost of producing a number of items x is given by C = mx + b , in which b is the fixed cost and m is the variable cost (the cost of producing one more item). … 
math,algebra,help
Problem states: Business and finance. The cost of producing a number of items x is given by C = mx + b, in which b is the fixed cost and m is the variable cost (the cost of producing one more item). (a)If the fixed cost is $40 and … 
business and finance
The cost of producing a number of items x is given by C=mx+b, inwhich b is the fixed cost and m is the variable cost (the cost of producing one more item). (a) If the fixed cost is $40 and the variable cost is $10, write the cost equation. … 
Math
How can you classify the 2 examples that you gave in part c? 
statistics
2. The director of admissions at a large university advises students that the cost of textbooks will average more than $300 for a typical semester. A random sample of 80 students enrolled in the university shows a sample mean cost … 
statistics
1. The oncampus housing costs for a semester at a state university are Normally distributed with a mean of $1553 and a standard deviation of $329. (a) What is the distribution of the mean oncampus housing cost for a semester at this … 
epoka university
1) The cost that is related to the particularly cost object and can be traced to it in an economically feasible (costeffective) way is called: o Indirect cost o Cost tracing o Direct cost o Variable cost 
Math
Let x be a random variable representing the monthly cost of joining a gym. We may assume that x has a normal distribution and that the population standard deviation is $5.20. A fitness magazine advertises that the mean monthly cost … 
math check
While writing an article on the high cost of college education, a reporter took a random sample of the cost of new textbooks for a semester. The random variable x is the cost of one book. Her sample data can be summarized by the following. … 
statistics
Describe whether the following study would most likely be “observational” or “experimental”, and why it would be so. A survey examines the preferences for laundry detergent. ***The admissions office wants to estimate the cost …