12. The 95% confidence interval for a population mean is between 6.3 and 7.7. What was the mean of the sample and margin of error that led to this confidence interval?

The mean of the sample was of 7 and the margin of error was of 0.7.

Step-by-step explanation:

Confidence interval concepts:

A confidence interval has two bounds, a lower bound and an upper bound.

A confidence interval is symmetric, which means that the point estimate used is the mid point between these two bounds, that is, the mean of the two bounds.

The margin of error is the subtraction between the bounds divided by 2.

In this question:

Lower bound: 6.3

Upper bound: 7.7

Mean of the sample is the point estimate, so: (6.3+7.7)/2 = 7

Margin of error: (7.7-6.3)/2 = 0.7

The mean of the sample was of 7 and the margin of error was of 0.7.

point a is the center of the circle that passes through points e, f, and g and the center of the circle that passes through points x, y, and z.

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.