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Gaugler - Learning Stats with R - 1/e (Homework)

James Finch

Statistics, section 2, Fall 2019

Instructor: Dr. Friendly

Current Score : 4 / 7

Due : Sunday, January 27, 2030 23:30 EST

Last Saved : n/a Saving...  ()

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Question
Points
1 2 3
3/3 1/2 –/2
Total
4/7 (57.1%)

  • Instructions

    This demo assignment allows many submissions and allows you to try another version of the same question for practice wherever the problem has randomized values.

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Assignment Submission

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Assignment Scoring

Your last submission is used for your score.

1. 3/3 points  |  Previous Answers GaLearnStats1 12.3.001.R. My Notes
Question Part
Points
Submissions Used
1 2 3
1/1 1/1 1/1
1/100 1/100 1/100
Total
3/3
 
This question is from Gaugler's "Learning Statistics with R," a free resource available to any instructor in WebAssign. The text will introduce learners to statistical data analysis using the R coding language, which is commonly used by statisticians in the real world.

Processors often preserve cucumbers by fermenting them in a low-salt brine (6%-9% salt) and then storing them in a high-salt brine until they are used to produce various types of pickles. The purpose of the high-salt brine is to slow softening of the pickles and to prevent freezing (if stored outside in cold climates).
Data showing the reduction in firmness of pickles stored over time in a low-salt brine are given in the accompanying table.
i 1 2 3 4 5
Weeks (x) in Storage 0 4 14 32 52
Firmness (y) in pounds 19.7 16.4 15.4 12.7 7.6
(a)
Use R to fit a least-squares line to the data. (Round your numeric values to three decimal places.)
ŷ =
−0.205x + 18.551
Correct: Your answer is correct.
(b)
As a check on your calculations, use R to plot the five data points and graph the line. Does the line appear to provide a good fit to the data points?
     Correct: Your answer is correct.
(c)
Use R and the least-squares line to estimate the mean firmness (in pounds) of pickles stored for 29 weeks. (Round your answer to one decimal place.)
Correct: Your answer is correct. pounds
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
2. 1/2 points  |  Previous Answers GaLearnStats1 3.1.011.R. My Notes
Question Part
Points
Submissions Used
1 2
1/1 0/1
1/100 1/100
Total
1/2
 
The manager of a stockroom in a factory has constructed the following probability distribution for the daily demand (number of times used) for a particular tool.
y 0 1 2
p(y)
 		0.1 0.6 0.3
It costs the factory $12 each time the tool is used. Use R to find the mean of the daily cost (in dollars) for use of the tool.
$ Correct: Your answer is correct.
Use R to find the variance of the daily cost for use of the tool.
Incorrect: Your answer is incorrect.
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
3. –/2 points GaLearnStats1 4.1.005.R. My Notes
Question Part
Points
Submissions Used
1 2
–/1 –/1
0/100 0/100
Total
–/2
 
One-hour carbon monoxide concentrations in air samples from a large city have an approximately exponential distribution with mean 3.4 ppm (parts per million). (Round your answers to five decimal places.)
(a)
Use R to find the probability that the carbon monoxide concentration exceeds 8 ppm during a randomly selected one-hour period.
(b)
A traffic-control strategy reduced the mean to 2.1 ppm. Use R to find the probability that the concentration exceeds 8 ppm.
Your work in question(s) will also be submitted or saved.
Viewing Saved Work Revert to Last Response
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