Answer:
Mean = 60
Standard Deviation = 6
Step-by-step explanation:
Number of bags = 25
Mean = x`= 30
Mean= Total number of sweets/ Total number of bags
30 = Total number of sweets/ 25
Total number of sweets= 30*25= 750
When the sweets are doubled then the number of sweets is 750 *2= 1500
Mean= Total number of sweets/ Total number of bags
Mean = 1500/ 25
Mean = 60 (twice the mean of 750 sweets = 30)
As x`= ∑x/n
But the new mean is calculated as
2x`= ∑( x.2)/n= 2. (30)= 60
The co efficient of Standard deviation is calculated as
Co efficient of SD = Standard Deviation/ Mean
= 3/30 = 0.1
Multiplying with the new mean would give
Co efficient of SD * Mean= Standard Deviation
60 *0.1 = 6
It is the property of the variance that when each observation is multiplied by the square of a constant <u>²</u> the variance also increase by <u>a² </u>and so does the standard deviation.
