Answer:
a) 
D. 9.74
b) 
B. 74
Step-by-step explanation:
Part a
We have the following dataset given:
69 74 75 62 70 93 64 69 61 88 67 77 87 90 66 91 77 63 82 82 71 74 76 65 83
We can begin calculating the sample mean with the following formula:

And replacing we got:

Now we can calculate the sample deviation with the following formula:

And after replace we got:

Part b
For this case we need to sort the value on increasing way:
[1] 61 62 63 64 65 66 67 69 69 70 71 74 74 75 76 77 77 82 82 83 87 88 90 91 93
And the median would be the value in the position 13 and we got:

Answer:c
Step-by-step explanation:
Answer:
72.8
Step-by-step explanation:
Let's solve your equation step-by-step.<span><span>−<span>5<span>(<span>x−4</span>)</span></span></span>=<span>−<span>30
</span></span></span>Step 1: Simplify both sides of the equation.<span><span>−<span>5<span>(<span>x−4</span>)</span></span></span>=<span>−30</span></span>
<span>Simplify: (Show steps)</span><span><span><span>−<span>5x</span></span>+20</span>=<span>−<span>30
</span></span></span>Step 2: Subtract 20 from both sides.<span><span><span><span>−<span>5x</span></span>+20</span>−20</span>=<span><span>−30</span>−20</span></span><span><span>−<span>5x</span></span>=<span>−<span>50
</span></span></span>Step 3: Divide both sides by -5.<span><span><span>−<span>5x</span></span><span>−5</span></span>=<span><span>−50</span><span>−5</span></span></span><span>x=<span>10
</span></span>Answer:<span>x=<span>10</span></span>