You believe that changes in bone density with age may increase the propensity of

Question

You believe that changes in bone density with age may increase the propensity of pedicle screws to loosen. You collect and separate data regarding the number of pedicle screws that last less than one year, between one and three years, or more than three years based on the age of the patient.

a. (4 pts) Use Minitab to test the hypothesis that the age of the patient does not affect the proportion of screws that last less than one year, between one and three years, or more than three years for a test level = 0.05.

b. (2 pts) Use the P-value from part A to determine whether or not you accept or reject the null hypothesis that the age of the patient does not affect how long pedicle screws last.

c. (2 pts) Use the test output from part A to determine which combination of age and duration pedicle screws last before loosening has the greatest deviation from the overall proportions regardless of age.

d. (4 pts) Use the Calc Probability Distributions menu to calculate the P-value obtained from the Minitab test in part A. You must show the Minitab output to receive full credit.

please show minitab output window!!

duration under 45 45 - 65 over 65 < 1 year 12 21 34 1 - 3 years 29 48 39 > 3 years 45 65 46

Explanation / Answer

Answer:

You believe that changes in bone density with age may increase the propensity of pedicle screws to loosen. You collect and separate data regarding the number of pedicle screws that last less than one year, between one and three years, or more than three years based on the age of the patient.

a. (4 pts) Use Minitab to test the hypothesis that the age of the patient does not affect the proportion of screws that last less than one year, between one and three years, or more than three years for a test level = 0.05.

hi-Square Test for Association: Worksheet rows, Worksheet columns

Rows: Worksheet rows   Columns: Worksheet columns

           C4      C5      C6 All

1          12      21      34   67

        17.00   26.48   23.52

       1.4691 1.1355 4.6706

2          29      48      39 116

        29.43   45.85   40.72

       0.0062 0.1006 0.0726

3          45      65      46 156

        39.58   61.66   54.76

       0.7436 0.1805 1.4017

All        86     134     119 339

Cell Contents:      Count

                    Expected count

                    Contribution to Chi-square

Pearson Chi-Square = 9.780, DF = 4, P-Value = 0.044

Likelihood Ratio Chi-Square = 9.513, DF = 4, P-Value = 0.049

Calculated chi square =9.78 > 9.488 the table value at 0.05 level. Ho is rejected

b. (2 pts) Use the P-value from part A to determine whether or not you accept or reject the null hypothesis that the age of the patient does not affect how long pedicle screws last.

Calculated P=0.044 < 0.05 level, Ho is rejected.

c. (2 pts) Use the test output from part A to determine which combination of age and duration pedicle screws last before loosening has the greatest deviation from the overall proportions regardless of age.

The combination, Duration < 1 year and age over 65 has the greatest deviation.

d. (4 pts) Use the Calc Probability Distributions menu to calculate the P-value obtained from the Minitab test in part A. You must show the Minitab output to receive full credit.

Cumulative Distribution Function

Chi-Square with 4 DF

   x P( X x )

9.78    0.955699

P( x>9.78) = 1-P( X 9.78) =1-0.955699

=0.044301

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.