The u. s. environmental protection agency (epa) is concerned about pollution caused by factories that burn sulfur-rich fuel. to decrease the impact on the environment, factory chimneys must be high enough to allow pollutants to dissipate over a larger area. assume the mean height of chimneys in these factories is 100 meters (an epa-acceptable height) with standard deviation 12 meters. a random sample of 40 chimney heights is obtained what is the probability that the sample mean height for the 40 chimneys is greater than 102 meters? what is the probability that the sample mean height is between 101 and 103 meters? suppose the sample mean is 98.5 meters. is there any evidence to suggest that the true mean height for chimneys is less than 100 meters?

solution:

as, mean is defined as sum of all the observations divided by total number of observations.

and , median is mid value of the data whether arranged in ascending order or descending order.

consider, roadsters:

2,3,4,5,6,7,8,9

mean =

also, median= , because number of observations is even, so median is mean of two mid values.

now, coming to bandits

2,3,4,5,6

mean =  

median = 4, as number of observations is odd.

so, roadsters has greater median as well mean than bandits.

→option a is true about the repairs performed on 2 types of cars:

bandits have lower median and mean than roadsters.

answer: bearing in mind that a rectangle has a perimeter of length + length + width + width.

step-by-step explanation:

p = perimeter

l = length

x=width

p = 2l + 2x

p = 2(l+x)     < ==== perimeter of the base of the box.

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: