1.
When performing
a regression analysis it’s important to look at the residual model diagnostics.
For each of the following residual plots, what should you look?Normal
probability plot
Residuals
vs. the fitted values
Histogram
Residuals
vs. the order of the data2.
Your company introduced several new
accessories for their top selling consumer product last quarter. Each accessory has a different price point.
You want to determine if the cost is a good predictor of sales. Perform a correlation and regression analysis
to determine the statistical relationship between the cost per item and the
number sold. Attach the output of your analysis. Include the conclusions drawn
from the results of the analysis.AccessoryNo. SoldCost per ItemA554115B294910C8849D86553.
A company develops a next generation product
line, but does not design it to six sigma capabilities. The next generation results in a lot of defects
and variation that is ultimately passed onto the customer. The customers experience a lot of in-field
defects causing them “heart burn”. The
number and length of calls into technical support increase for the next generation
dramatically, thereby costing the company a lot more money. Based on the data (Analyze challenge Data.xls – Next gen product line tab), answer the
following questions and attach the output of your analysis.Perform
a correlation and regression analysis to determine the statistical
relationship between the increase length of call and the cost to the
company.
Determine
the difference in the relationship between the cost to the company with
the new product versus the cost to the company with the old product. Comment about the difference.
What
other analytical tools do you recommend to determine if there is a
significant difference that the new product is costing the company versus
the old product? Explain why and
how the tools would determine if there is a statistical significance.
Based
on these results, what are your next steps as the project leader?4.
Your department has 5 operators on one
assembly line producing the same product. Each has different levels of
experience. Defect data from the past month is summarized below. Is there a
statistically significant difference in the number of defects between operators?Operator
1Operator
2Operator
3Operator
4Operator
5#
Defects10815108#
Good150155160163160Conduct the
appropriate hypothesis test and attach the output of your analysis. Include the conclusions drawn from the
results of the analysis. Based on your
results, what are the next steps?5.
Customers place orders via customer service
rep or on-line (electronically). The
orders and the total number of successes (or “error free” orders) were tracked
for the past 6 months. The results are
below. Is there a statistically
significant difference in errors between orders placed via CSR versus electronically?
Orders CSR # Success Orders Electronically # Success
1222 1200 1576 1570
1101 1100 1203 1101
1120 1099 1304 1268
1298 1201 1290 1245
1280 1200 1275 1200
1178 1175 1203 1197
Answer the following:Ho =
Ha =Type
of data =
Type
of analysis =
Confidence
level anda risk =Conduct
the appropriate hypothesis test and attach the output of your analysis. Include
the conclusions drawn from the results of the analysis. Based on your results, what are the next
steps for this project?6.
Correlation and regression determines the
relationship between 2 variables, but the output does not determine statistical
significance.Answer True (T) or False
(F)7.
The higher the R squared value, the less the
statistical relationship.Answer True
(T) or False (F)8.
A
scatter plot also determines statistical significance between two variables.Answer
True (T) or False (F)9.
What does the confidence level determine (in
simple terms)?10. Determine
thea risk for each of the confidence levels
below:
Confidence Level arisk
95% _____
90% _____
80% _____
99% _____11. If the
confidence level is 90% and the p-value is 0.08, what conclusions can you draw?12. Chi square
testing is used with ______ (attribute or variable) data and ____ sample size.13. Identify 3
advantages and 3 disadvantages of EVOP14. A rancher wants to estimate the average weight gain of cattle he takes to
market. He selects a sample of 16
cattle. What is his confidence interval for weight gain?221 284 245
254 239 182
298 290 272
259 271 239
237 259 210
21115. Tire Mart receives a shipment of
100 tires from a manufacturer. Within 3 months they receive 7 tires back as
defective. The over head of replacing a tire is $18. How much should they budget to cover the
maximum cost of potential claims for their next order of 100 tires from this
manufacturer?16. Your department has 3 assembly lines and recently has had a problem with
machine downtime. Using thedata (Analyze
Challenge Data.xls -Confidence Int
Downtime tab),answer the following questions and
attach the output of your analysis.
Include the conclusions drawn from the
results of the analysis
a. Find the confidence interval on downtime.
b. Find the confidence interval on the variance.
c. Run an ANOVA (GLM) on the data set below.
Is there a significant factor?17. A survey
was conducted to determine if there is a difference in customer satisfaction
levels by region. The survey responses
weresatisfied,dissatisfied orneutral.
A Chi square analysis for 5 regions shows there was is not a statistically
significant difference in customer satisfaction by region. However the p- value
is 0.076 so you decide to do further analysis. Complete the table below. What
conclusions are drawn from the results?
(df = 2)RegionChi square TotalCum ProbP valueA0.252B4.614C3.715D2.84218. A supplier
claims an improvement in part diameter from a new machining process. The
average diameter is 33.5 (compared to 36.5 from the old process) with a
standard deviation of 1.02. How many
samples are needed to validate thisclaim?
Acceptable test risks are 5% alpha and 10% beta.19. One of
your key customers has complained that 5% of the orders received are incorrect.
You’ve changed the customer order process to reduce incorrect orders to
1%. How many orders will you need to
look at to detect this improvement?