Reference no: EM131238615
The failure of an O-ring on the space shuttle Challenger's booster rockets led to its destruction in 1986. Using data on previous space shuttle launches, Dalal et al. (1989) examine the probability of an O-ring failure as a function of temperature at launch and combustion pressure. Data from their paper is included in the challenger.csv file. Below are the variables:
• Flight: Flight number
• Temp: Temperature (F) at launch
• Pressure: Combustion pressure (psi)
• O.ring: Number of primary field O-ring failures
• Number: Total number of primary field O-rings (six total, three each for the two booster rockets)
The response variable is O.ring, and the explanatory variables are Temp and Pressure. Complete the following:
(a) The authors use logistic regression to estimate the probability an O-ring will fail. In order to use this model, the authors needed to assume that each O-ring is independent for each launch. Discuss why this assumption is necessary and the potential problems with it. Note that a subsequent analysis helped to alleviate the authors' concerns about independence.
(b) Estimate the logistic regression model using the explanatory variables in a linear form.
(c) Perform LRTs to judge the importance of the explanatory variables in the model.
(d) The authors chose to remove Pressure from the model based on the LRTs. Based on your results, discuss why you think this was done. Are there any potential problems with removing this variable?
Describe how well the model fits the data
: Estimate a logistic regression model using the picloram amount as the explanatory variable and the number of weeds killed as the response variable.
|
Compare and contrast the retail value
: From the e-Activity, compare and contrast the retail value and the value chain of Abercrombie & Fitch Co. Determine key qualities that you believe the company exhibits in relationship building that may influence the performance of this retailer.
|
What are you most proud of about your cultural heritage
: Compare and contrast your family values, worldviews, and practices with those of some of the families whose ethnicities differ from yours, and provide your reflection. You may use examples form the text for examples of ethnicities different from y..
|
Calculate the amplifier gain
: Obtain an expression for G = V0/Vs in terms of β. - Calculate the amplifier gain for β = 0.0, β = 0.5, and β =1.0 with component values R1=10 kΩ and R2 = 1.5 kΩ.
|
Are there any potential problems with removing this variable
: The authors chose to remove Pressure from the model based on the LRTs. Based on your results, discuss why you think this was done. Are there any potential problems with removing this variable?
|
Explain elements of organisational culture at al amalia
: Explain elements of organisational culture at Al Amalia - Apply another model of organizational culture and justify how this shapes current management approaches of Al Amalia - Assess the importance of the relationship between organisational culture ..
|
Are there any famous indigenous celebrities out there
: Define religion, and discuss why it is useful in society. Explain why it is important for you personally to understand the beliefs of other religious groups. How might a knowledge of religion be useful in your workplace?
|
What was your percentile score on this test
: She informs you that your z score was 1.10. What was your percentile score on this test? (enter a number only, rounded to the nearest 2 decimal places.
|
Calculate the log-likelihood function
: Compare the estimated standard errors resulting from the use of optim() to those obtained from glm(). Repeat this process with the corresponding complementary log-log regression model.
|