A sports writer wants to see if a football filled with helium travels farther, on average, than a football filled with air. 15 footballs were filled with helium to the recommend pressure and 11 footballs were filled with air to the recommended pressure. The mean yardage for the helium filled footballs was 232 yards with a standard deviation of 2 yards. The mean yardage for the air filled footballs was 261 yards with a standard deviation of 4 yards. Assume the populations are normal with equal variances. Required:
a. Construct a 80% confidence interval for the mean difference in in yardage for the two types of footballs Lower bound
b. What can you conclude about the sports writer's idea that helimum footballs travel farther, on average?

choice b is correct

step-by-step explanation:

we have been given the following system of inequalities;

we are required to graph the solution to the system of inequalities. using a graphing tool, the graph of the system is as shown in the attachment. the continuous line represents the graph of while the dotted line represents .

i am unable to solve this problem

step-by-step explanation:

7

step-by-step explanation:

the answer would be 7

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18