Question Recent studies have shown that Punica granatum (or pomegranate) seeds have germination time that is found to be normally distributed. To verify this, a biologist measured the number of days to germination of 20 random pomegranate seeds. Below shows the data obtained:   15.82  16.69  17.69  18.14  19.38  16.07  16.89  17.98  18.33  19.48  16.49  17.30  18.10  18.50  19.55  16.67  17.67  18.11  19.35  20.66    Using visual inspection with the given histogram and Q-Q Plot below, do the data show evidence that the germination time of pomegranate seeds follows the normal distribution? Explain by interpreting each graph.                              Figure 1. Histogram                        Figure 2. Q-Q Plot    2. Using the Wilk-Shapiro Test with R software output given below, do the data show evidence that the germination time of pomegranate seeds follows the normal distribution at ?=1%? Complete the following steps: Shapiro-Wilk normality test data: time W = 0.9693 ,   p-value = 0.7401                             Ho:   Ha:   Decision Rule:  p-value:   Decision:   Conclusion:   3. Find a point estimate of the true mean germination time of pomegranate seeds.     4. Given the R software output below, interpret the 90% confidence interval about the true mean germination time of pomegranate seeds. 90 percent confidence interval: 17.44249             18.44451   5. Given the R software output below, is there sufficient evidence to say that the mean germination time of pomegranate seeds is not equal to 18 days, at 5% level of significance? Explain briefly.   95 percent confidence interval:      17.33705           18.54995     6. What happened to the confidence interval after increasing the confidence level? Give the width of the 90% and 95% confidence intervals. 7. At 5% level of significance, test from the data if the mean germination time of pomegranate seeds is not equal to 18 days using the given R-software output: One Sample t- test Data: time t = -0.195 ,   df = 19, p-value = 0.8475 alternative hypothesis: true mean is not equal to 18   Note: write Ho and Ha both in symbols and in words.  Ho:   Ha:   Test procedure:   Decision Rule:   Computed test statistic and p-value:   Decision:   Conclusion:     8. Relate the computed confidence interval (item #5) with the conclusion using the result of the test statistic (p-value) (item #7). Do they give similar conclusion?

Mathematics For Machine Technology
8th Edition
ISBN:9781337798310
Author:Peterson, John.
Publisher:Peterson, John.
Chapter29: Tolerance, Clearance, And Interference
Section: Chapter Questions
Problem 16A: Spacers are manufactured to the mean dimension and tolerance shown in Figure 29-12. An inspector...
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Recent studies have shown that Punica granatum (or pomegranate) seeds have germination time that is found to be normally distributed. To verify this, a biologist measured the number of days to germination of 20 random pomegranate seeds. Below shows the data obtained:  

15.82 

16.69 

17.69 

18.14 

19.38 

16.07 

16.89 

17.98 

18.33 

19.48 

16.49 

17.30 

18.10 

18.50 

19.55 

16.67 

17.67 

18.11 

19.35 

20.66 

 

  1. Using visual inspection with the given histogram and Q-Q Plot below, do the data show evidence that the germination time of pomegranate seeds follows the normal distribution? Explain by interpreting each graph.

       

                     Figure 1. Histogram                        Figure 2. Q-Q Plot 

 

2. Using the Wilk-Shapiro Test with R software output given below, do the data show evidence that the germination time of pomegranate seeds follows the normal distribution at ?=1%? Complete the following steps:

Shapiro-Wilk normality test

data: time

W = 0.9693 ,   p-value = 0.7401

                           

Ho:  

Ha:  

Decision Rule: 

p-value:  

Decision:  

Conclusion:  

3. Find a point estimate of the true mean germination time of pomegranate seeds.

 

 

4. Given the R software output below, interpret the 90% confidence interval about the true mean germination time of pomegranate seeds.

90 percent confidence interval:

17.44249             18.44451

 

5. Given the R software output below, is there sufficient evidence to say that the mean germination time of pomegranate seeds is not equal to 18 days, at 5% level of significance? Explain briefly.

 

95 percent confidence interval:

     17.33705           18.54995

 

 

6. What happened to the confidence interval after increasing the confidence level? Give the width of the 90% and 95% confidence intervals.

7. At 5% level of significance, test from the data if the mean germination time of pomegranate seeds is not equal to 18 days using the given R-software output:

One Sample t- test

Data: time

t = -0.195 ,   df = 19, p-value = 0.8475

alternative hypothesis: true mean is not equal to 18

 

Note: write Ho and Ha both in symbols and in words. 

Ho:  

Ha:  

Test procedure:  

Decision Rule:  

Computed test statistic and p-value:  

Decision:  

Conclusion:  

 

8. Relate the computed confidence interval (item #5) with the conclusion using the result of the test statistic (p-value) (item #7). Do they give similar conclusion?

 
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