The answers are A and B, -5 and -1. Hope this helps!
To get the variance, start with finding the mean of your data points:
(23 + 19 + 22 + 30 + 28) / 5 = 24.4
Now take each data point and subtract the mean from it, then square that value:
23 - 24.4 = -1.4 * -1.4 = 1.96
19 - 24.4 = -5.4 * -5.4 = 29.16
22 - 24.4 = -2.4 * -2.4 = 5.76
30 - 24.4 = 5.6 * 5.6 = 31.36
28 - 24.4 = 3.6 * 3.6 = 12.96
Now get the average of those new numbers. That is your variance:
(1.96 + 29.16 + 5.76 + 31.36 + 12.96) / 5 = 16.24
The standard deviation will be the square root of the variance:
√(16.24) = 4.0299 (rounded to 4DP)
Answer:
We can model the decimal number 1.7 by drawing two squares and divide each of the two squares into 10 equal parts.
Then we start shading the square such that the first square is fully shaded and in the second square we shade 7 out of the 10 parts such that 0.7 of the figure is shaded.
Hence, the total portion of the figures that are shaded are:
1+0.7=1.7
In math the fraction 5/6 means 5 and 6 tenths.
