Answer:
Rational numbers
Step-by-step explanation I put D on a test and I got it right
From the given mean and margin of error, the 99% confidence interval for the mean amount of money spent on lunch per week for all students is:
[$19.5, $22.5].
<h3>How to calculate a confidence interval given the sample mean and the margin of error?</h3>
The confidence interval is given by the sample mean plus/minus the margin of error, hence:
- The lower bound is the sample mean subtracted by the margin of error.
- The upper bound is the sample mean added to the margin of error.
For this problem, we have that:
- The sample mean is of $21.
- The margin of error is of $1.50.
Hence the bounds are given as follows:
- Lower bound: 21 - 1.50 = $19.50.
- Upper bound: 21 + 1.50 = $22.50.
Hence the interval is [$19.50, $22.50].
More can be learned about confidence intervals at brainly.com/question/25890103
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What are you trying to work out?
Given the angle

angle

is equivalent to angle 135 degrees and angle 135 degrees is equvalent to angle 45 degrees in the second quadrant, thus sine is positive but cosine and tangent are negative.