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Woodworkers Alex and Brandon make precision pieces for various toys. One of the

ID: 3331900 • Letter: W

Question

Woodworkers Alex and Brandon make precision pieces for various toys. One of the toys they make requires four 8-inch long sticks. When Alex makes 8-inch long sticks, he cuts them one at a time and tosses them into a storage bin. Alex’s sticks have a mean length of 8.10 inches and a standard deviation of 0.15 inches. Brandon uses a different approach. He wants his four 8-inch sticks to be identical, so he makes them by clamping together 4 boards and then cutting them all at once. After each cut, Brandon measures the sticks while they are still clamped together (and all 4 are given the same measurement). His cuts have a mean length of 8.05 inches and a standard deviation of 0.1 inches.

 

a.   Suppose we take 1 of Alex’s sticks, 2 of Brandon’s sticks (both from the same cut), lay them end to end, and measure the combined length.

 

The mean length will be ___________________.

 

The standard deviation of the length will be __________________.

 

 

b.   Suppose we take 1 of Alex’s sticks, 2 of Brandon’s sticks (from different cuts), lay them end to end, and measure the combined length.

 

The mean length will be ___________________.

 

The standard deviation of the length will be __________________.

Explanation / Answer

a)

i)

The mean length will be 8.1

The standard deviation of the length will be 0.15

b.   Suppose we take 1 of Alex’s sticks, 2 of Brandon’s sticks (from different cuts), lay them end to end, and measure the combined length.

The mean length will be 8.05

The standard deviation of the length will be 0.1