Exercise \#2. Calculate confidence intervals for the population mean when you do not know the population standard deviation. Use the following information to complete the calculations. Show your work. Formula: \( \bar{x} \pm t\left(\frac{s}{\sqrt{n}}\right) \) (2a) Assume the following: \( \bar{x}=60 \mathrm{~s}=7 \quad n=81 \) Calculate confidence intervals for a \( 95 \% \) confidence level. Calculate confidence intervals for a 99\% confidence level.

Which one of the following hypotheses is/are valid? 1. \( H_{0}: \mu \leq 100 ; H_{1}: \mu \geq 100 \) 2. \( H_{0}: \mu=120 ; H_{1}: \mu \neq 120 \) 3. \( H_{0}: \mu \neq 130 ; H_{1}: \mu=130 \) 4. \( H_{0}: \bar{X} \leq 210 ; H_{1}: \bar{X}>210 \) 5. \( H_{0}: p \neq 0.42 ; H_{1}: p=0.42 \)

Clarissa has just completed her second semester in college. She earned a grade of B in her 3 -hour calculus course, a grade of C in her 5 -hour economics course, a grade of B in her 4 -hour engineering course, and a grade of C in her 3 -hour studio art course. Assuming that A equals 4 points, B equals 3 points, C equals 2 points, D equals 1 point, and F is worth no points, determine Clarissa's grade-point average for the semester. Clarissa's grade point average is 2.47 . (Round to two decimal places as needed.)

Resullic los siguientes dicarious con nanomios \( 4 x^{2}+6 y+46 x^{3}+5 x-40 x^{2}-2 x+x^{3}= \)

60 Développer et réduire les expressions suivantes. a) \( (x+7)^{2}+2 x+4 \) b) \( -3(x-4)^{2}+11 \) c) \( (2 x-5)(2 x+5)-(3 x+5)^{2} \) d) \( (x-1)^{2}(x+2) \)

\( 2 \sqrt { 3 + 2 \sqrt { 3 + 2 \sqrt { 3 + 2 \sqrt { 3 + 2 \sqrt { 3 + \ldots } } } } } \)