X+x+20+2x=180
4x+20=180
4x=160
x=40
The answer to this question is 30.
Https://us-static.z-dn.net/files/d98/91a920cfe56638bfcc2f4c5b8ab8fcb3.jpeg
<span>mean: ( 9 + 7 + 6.5 + 7.5 + 7 + 8 + 5 + 6 + 7.5 + 8 ) : 10 = 7.15Variance:(Sigma)² = ( 1.85² + 0.15² + 0.65² + 0.35² + 0.15² + 0.85² + 2.15² + 1.15² + 0.35² + 0.85² ) : 10 ≈ 1.15Answer: C ) 1.15</span>
Answer:
3
Step-by-step explanation:
Mean = (3+7+-1+1+0+5+-3+2+-1+6+5+-2)/12
= 1.833
median is middle of ordered numbers -3/-2/-1/-1/0/1/2/3/5/5/6/8/7 here between the 6th and the 7th since with even number sample, there is not a unique middle. This would be 1.5
Standard deviation = √ 123.67/12
√10.3
=3.21
the change score that is 2.2 standard deviations below the mean.
1.83 - 2.2(3.21)
= 5.232
