# Math check

posted by .

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.

## Similar Questions

1. ### 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). …
2. ### 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 …

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. …
4. ### Math

How can you classify the 2 examples that you gave in part c?
5. ### 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 …
6. ### statistics

1. The on-campus 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 on-campus housing cost for a semester at this …
7. ### epoka university

1) The cost that is related to the particularly cost object and can be traced to it in an economically feasible (cost-effective) way is called: o Indirect cost o Cost tracing o Direct cost o Variable cost
8. ### 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 …
9. ### 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. …
10. ### 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 …

More Similar Questions

Post a New Question