Please tell me if my answers are correct; if not correct please provide correct answer and rationale. thank you very much.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7844949/

1. What is the research hypothesis or research question? (5 pts)

Research hypothesis: The Minimally Invasive Surgery Total Knee Arthroplasty (MIS TKA) provide long-term clinical and radiographic outcomes and good survival.

Research question: Does the Minimally Invasive Surgery Total Knee Arthroplasty (MIS TKA) provide long-term clinical and radiographic outcomes and good survival?

Null hypothesis: The Minimally Invasive Surgery Total Knee Arthroplasty (MIS TKA) does not provide long-term clinical and radiographic outcomes and good survival.

2. What are the main study variable(s)? How would you describe the variables (independent vs dependent; what level of measurement are they; are they continuous or discrete; etc)? (5 pts)

Main study variables for the Kaplan Meier survival analysis include survival rate (dependent variable, continuous, ratio level of data) and follow-up years (independent variable, continuous, ratio level of data).

Main study variables for the paired t test include range of motion (dependent variable, continuous, ratio level of data), and operation status (pre or post-operativeindependent variable, nominal level of data).

Additional study variables include the participants age (continuous, ratio level of data), gender (male or female; nominal level of date), height (continuous, ratio level of data), body mass index (continuous, ratio level of data), size of the posterior femoral cut (continuous, ratio level of data), and length of the anteroposterior femur (continuous, ratio level of data).

3. What statistical test was used? (5 pts)

A paired t test was performed to compare preoperative and postoperative range of motion (ROM).

A Kaplan Meier survival analysis was used to determine the cumulative rate of prosthesis survival during the study period.

4. What conclusions were made based on the results of the statistical test? (5 pts)

The paired t test supports that the ROM increased postoperatively; mean extension and flexion angles were increased from extension angle preoperatively (97) to postoperatively(12) andflexion angle preoperatively (10618) to postoperatively(12411). See Table 1.

The Kaplan Meier analysis supports that the projected rate of survival to revision was 94.7% at 12 years after MIS TKA. There was a 95% confidence interval, 0.90- 0.99. See Figure 5.

5. Provide the citation for the article in APA format. (3 pts)

Toyoda S., Kaneko T., Mochizuki Y., Hada M., Takada K., Ikegami H., & Musha Y. (2021).

Minimally invasive surgery total knee arthroplasty is less popular, but the prosthesis designed specifically for MIS provides good survival and PROMs with a minimum follow-up of 10 years. Journal of Orthopaedic Surgery and Research, 16(1), 1-9.https://doi-org.uc.idm.oclc.org/10.1186/s13018-021-02254-3