Probability and Statistics : Scatter Plot, Line of Best Fit, Extrapolation and Forecasting
Not what you're looking for?
11. An automaker guarantees its particular type of automotive transmissions for 90,000 km. Tests have shown that such transmissions have an average life of 135,000 km with a standard deviation of 22,500 km. If the lives of these transmissions are normally distributed, what is the probability that a car will be returned to the company for transmission work while it is still under warranty?
12. The B.A. Company sells an imported desk calculator on a franchise basis and performs preventive maintenance and repair service on this calculator. The data below have been collected from 17 recent calls on users to perform routine preventive maintenance service. For each call, information was collected on the number of machines serviced and the total time (in minutes) spent by the service person:
Observation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
# Machines 7 6 5 1 5 4 7 4 2 8 5 2 5 7 1 4 5
# Minutes 97 86 78 10 75 62 101 53 33 118 65 25 71 105 17 49 68
a. Create a scatter plot of these data to investigate the relationship between how many machines an office has and how long it takes to perform preventative maintenance. Put # Machines on the x-axis and # Minutes on the y-axis.
b. Use a straightedge to sketch the line that seems to best approximate the data points. Then estimate the slope and the y-intercept of that line, and write the equation of the line you sketched.
Use the line from b. to predict the time needed to perform routine preventive maintenance for an office with 3 machines
Purchase this Solution
Solution Summary
Scatter Plots, Lines of Best Fit, Extrapolation and Forecasting are investigated. The solution is detailed and well presented.
Education
- BSc , Wuhan Univ. China
- MA, Shandong Univ.
Recent Feedback
- "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
- "excellent work"
- "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
- "Thank you"
- "Thank you very much for your valuable time and assistance!"
Purchase this Solution
Free BrainMass Quizzes
Terms and Definitions for Statistics
This quiz covers basic terms and definitions of statistics.
Measures of Central Tendency
Tests knowledge of the three main measures of central tendency, including some simple calculation questions.
Measures of Central Tendency
This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.
Know Your Statistical Concepts
Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.