The four sides of a printed circuit board (PCB) enclosure consist of two pieces selected from a population whose mean length is
30 cm with standard deviation 0.14, and two pieces selected from a population whose mean length is 45 cm with standard deviation 0.31 cm. Assuming the four pieces are chosen independently, the standard deviation of the perimeter is
1 answer:
Answer:
Step-by-step explanation:
let X1,X2 represents the length of two pieces selected from a population
the mean and standaerd deviation for the length of these two pieces X1,X2 is 30 cm and 0.14 cm
let X2,X3 represents the length of two pieces selected from a population
the mean and standaerd deviation for the length of these two pieces X2,X3 is 45 cm and 0.31 cm
To be continued on the attachment:
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Answer and Explanation:
Given : A store sells different kinds of candy at $1, $1.50, $2, and $3 per kilogram.
To find : How many kilograms of each kind of candy does $3 buy?
Explain why the price of 1 kg and the amount of candy that $3 can buy are inversely proportional quantities?
Solution :
The total amount spent on buying candies is $3.
A store sells different kinds of candy at $1, $1.50, $2, and $3 per kilogram.
When the cost of candies is $1 per kg.
Amount of candies bought is
When the cost of candies is $1.50 per kg.
Amount of candies bought is
When the cost of candies is $2 per kg.
Amount of candies bought is
When the cost of candies is $3 per kg.
Amount of candies bought is
The amount spent on candies is constant.
The difference in the unit price of candies = 3-2=1
The difference in the amount of candies = 1-1.5=-0.5
The negative sign indicates the inverse proportionality.