Answer:
Mean=50.
standard deviation=50.
Step-by-step explanation:
Let the perfect score be 100.
The mean(average) of a data is given by: 
Here the number of data points are 100. out of which 50 attains a value 100,and 50 attains value 0.
so, sum of data points=50×100+50×0=5000.

Mean=50.
"Now the standard deviation of data points are calculated by firstly subtracting mean from every entry and then square the number and take it as new entry and calculate the mean of the new data entry and lastly taking the square root of this new mean".
Here if 50 is subtracted from each entry the new entry will have 50 entries as '50' and 50 entries as '-50'.
next on squaring we will have all the 100 entries as '2500'.
now the mean of these entries is: 
=2500
taking it's squareroot we have 
Hence, standard deviation=50.
Answer:
x=14
Step-by-step explanation:
45 = 3 (x + 1)
Distribute the 3 to both terms in the parentheses
45 = 3x +3
Subtract 3 from each side
45-3 = 3x+3-3
42 = 3x
Divide each side by 3
42/3 = 3x/3
14 =x
Answer:
12 inches
Step-by-step explanation:
To solve you have to set up a ratio. Because both buildings are being shrunk the exact same amount, you just have to account for the size difference from the miniature and real life. The ratio is 21:3 and 84:x. To find x you just have to cross multiply and solve.
The equation comes out to be 252 = 21x
Divide both sides by 21 to get x.
252/21 = 12
The size of the 84 foot building as a model is 12 inches.
14. [-27, 0, 1.728, 125]
15. [ 18, 15, 13.8, 10]
16. [-3.9, 0, 1.56, 6.5]
17. [9, 0, 1.44, 25]
18. [12, 0, -4.8, -20]
19. [10, 1, 2.44, 26]
20. [64, 25, 14.44. 0]
21. [-22, -4, 3.2, 26]