Aschool teacher is worried that the concentration of dangerous, cancer-causing radon gas in her classroom is greater than the safe level of 4pci/l. the school samples the air for 36 days and finds an average concentration of 4.4pci/l with a standard deviation of 1pci/l. at a 5% significance level, the critical value(s) is (are)

Use the frequency distribution, which shows the number of american voters (in millions) according to age, to find the probability that a voter chosen at random is in the 18 to 20 years old age range. ages frequency 18 to 20 5.9 21 to 24 7.7 25 to 34 20.4 35 to 44 25.1 45 to 64 54.4 65 and over 27.7 the probability that a voter chosen at random is in the 18 to 20 years old age range is nothing. (round to three decimal places as needed.)

Amodel rocket is launched from a roof into a large field. the path of the rocket can be modeled by the equation y = -0.04x^2 + 8.6x + 4.8, where x is the horizontal distance, in meters, from the starting point on the roof and y is the height, in meters, of the rocket above the ground. how far horizontally from its starting point will the rocket land? a. 0.56 m b. 215.56 m c. 431.11 m d. 215.74 m

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28