A 90% confidence interval for the mean height of students
is (60.128, 69.397). What is the value of the margin of error?
a) m = 129.525
b) m = 4.635
c) m = 64.763
d) m = 9.269

And the best answer on this case would be:

b) m = 4.635

Step-by-step explanation:

Let X the random variable of interest and we know that the confidence interval for the population mean is given by this formula:

The confidence level on this case is 0.9 and the significance

The confidence interval calculated on this case is

The margin of error for this confidence interval is given by:

Since the confidence interval is symmetrical we can estimate the margin of error with the following formula:

Where Upper and Lower represent the bounds for the confidence interval calculated and replacing we got:

And the best answer on this case would be:

b) m = 4.635

3< x< 5

step-by-step explanation:

|x - 4| < 1

there are two solutions, one positive and one negative.   remember to flip the inequality when taking the negative solution

x-4 < 1       x-4 > -1

add 4 to each side

x-4+4 < 1+4       x-4+4 > -1+4

x< 5                 x> 3

3< x< 5