白痴數學問題,mode同standard deviation點計?

例: 4,5,5,6
mode = 出現最多的數字, 即係 5
standard deviation:
先找mean = (4+5+5+6)/4 = 5
再用公式找variance: summation [square(x-mean)] / total numbers
= [squ(4-5) + squ(5-5) + squ(5-5) + squ(6-5)]/4
= [1+0+0+1]/4
= 0.5
standard deviation = square root [variance]
= squ_root[0.5]
= 0.707

Q1. The mode of a set of data is the value in the set that occurs most often.
Example: The following is the number of problems that Ms. Matty assigned for homework on 10 different days. What is the mode?
8, 11, 9, 14, 9, 15, 18, 6, 9, 10
Solution: Ordering the data from least to greatest, we get:
6, 8, 9, 9, 9, 10, 11 14, 15, 18
Answer: The mode is 9.

Q2. The standard deviation is the root mean square (RMS) deviation of values from their arithmetic mean.
Example: In the population {4, 8}, the mean is 6 and the deviations from mean are {-2, 2}. Those deviations squared are {4, 4} the average of which (the variance) is 4. Therefore, the standard deviation is 2. In this case 100% of the values in the population are at one standard deviation of the mean.

mode is the data that hv the most time, eg, 2,2,3,5, then mode is 2
SD u can use calculator use SD mode, after enter data, use shift +2 if fx50f