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:
IJ = 12
Step-by-step explanation:
sum the parts of the ratios, 3 + 3 + 4 = 10 parts
Divide HK by 10 to find the value of one part of the ratio.
40 ÷ 10 = 4 ← value of 1 part of ratio , then
IJ = 3 parts = 3 × 4 = 12
Answer:
The 80% confidence interval for difference between two means is (0.85, 1.55).
Step-by-step explanation:
The (1 - <em>α</em>) % confidence interval for difference between two means is:

Given:

Confidence level = 80%

*Use a <em>t</em>-table for the critical value.
Compute the 80% confidence interval for difference between two means as follows:

Thus, the 80% confidence interval for difference between two means is (0.85, 1.55).
There is 60% of red t-shirts 40% of them are white and blue so the reds are 60%
4x²+4x-35=0
factor: (2x+7)(2x-5)=0
2x+7=0, or 2x-5=0
2x=-7 or 2x=5
x=-3.5 or x=2.5
I don't see any rounding necessary in this case.
when you factor ax²+bx+c, you take the two factors of a and the two factors of c, one factor of a times one factor of c, the other factor of a times the other factors, the sum of the two products make b.
in this case, the factors of 4 is 2 and 2, the factors of -35 is -5 and 7. I line them up in the following way:
2 -5
2 7
then I multiple them diagonally, the top left 2 multiplying the bottom right 7=14, and the other 2 multiplying -5=-10, 14 and -10 make a sum of 4.
if you don't get the desired sum, switch the factors up and down till you have the right combination. Note: Do not switch left and right.
I hope this makes sense to you.