<span>Standard deviation is the square root of variance. Variance is always a non-negative number, since you can't take the square root of a negative number. So neither can be negative </span>
The answer is:
11) The midpoint is (0,3)
12) The midpoint is (1,3)
Answer:1/6 plus 1/6 is 1/3
Step-by-step explanation:
Answer:
B : 850
Step-by-step explanation:
Using the z-distribution, the test statistic is:
c) -2.63.
<h3>What are the hypothesis tested?</h3>
At the null hypothesis we test if the means are equal, equivalent to a subtraction of 0, hence:

At the alternative hypothesis, we test if they are different, hence:

<h3>What are the mean and the standard error for the distribution of differences?</h3>
For each sample, they are given as follows:
.
.
For the distribution of differences, it is given by:
.
<h3>What is the test statistic?</h3>
The test statistic is given by:

In which
is the value tested at the null hypothesis.
Hence:


z = -2.63.
More can be learned about the z-distribution at brainly.com/question/13873630
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