In an environmental impact study for a new airport, the noise levels of various jets were measured just seconds after their wheels left the ground. the jets were either wide-bodied or narrow-bodied. the noise levels in decibels (db) are recorded here for 15 wide-bodied jets and 12 narrow-bodied jets. wide-bodied jets 109.5 107.3 105.0 117.3 105.4 113.7 121.7 109.2 108.1 106.4 104.6 110.5 110.9 111.0 112.4 narrow-bodied jets 131.4 126.8 114.1 126.9 108.2 122.0 106.9 116.3 115.5 111.6 124.5 116.2

a. do the two types of jets have different mean noise levels? report the level of significance of the test.

b. estimate the size of the difference in mean noise levels between the two types of jets using a 95% confidence interval.

c. how would you select the jets for inclusion in this study?

step-by-step explanation:

my butt

third choice down

step-by-step explanation:

the first inequality is based on the number of adults and campers, and the second inequality is based on the cost of feeding both the adult and the camper.

we know that there is room for 525 people max.   it's ok to have less than 525, but it's not ok to have more than 525, so the inequality is less than or equal to.   the number combination of adults (x) and campers (y) cannot exceed this 525 max.   therefore:

x + y ≤ 525

now we talk about cost.   it costs $9 to feed one adult, so depending upon the number of adults you have (x) depends upon how much it will cost to feed that number of adults.   same with the campers, who cost $5 to feed.   the adults can be represented by 9x and the campers can be represented by 5y.   since the budget cannot exceed 1,200, the second inequality is:

9x + 5y ≤ 1200