Height was measured in two groups, and plotted using density plots and histograms:

Which of the following statements is true?

A study was conducted in males who underwent prostatectomy for treatment of prostate cancer. A prostatectomy is a surgical procedure for the partial or complete removal of the prostate.

Data from 316 participants have been saved in the Datasets section of the course Sharepoint page as:

Assessment data > Quizzes > Quiz 1 > prostate.rds

The datasets contain the following variables:

• age: participant age (years)
• size: the size of the participant’s prostate (grams)

• preop_psa: preoperative

  prostate specific antigen (PSA) (ng/mL)

• time_to_recurrence: time to recurrence of prostate cancer, or

  withdrawal from the study, whichever came first (months)

Calculate the median and interquartile range time to recurrence.

The 2016 National Drug Strategy Household Survey reports that 15.6% of Australians have used an illicit drug in the last year. If a researcher asks 10 randomly selected people about their use of illicit drugs, what is the probability that 5 or more report having used  illicit drugs in the past year?

The Air Quality Index (AQI) is a measure of air pollution, combining measurements of ozone, carbon monoxide, sulfur dioxide, nitrogen dioxide, airborne particles and visibility into a single index. The AQI for 420 days measured in the Illawarra region, NSW was plotted and summarised below.

Figure: Density plot of Air Quality Index for Illawarra

Figure: Box plot of Air Quality Index for Illawarra

Descriptive statistics

Which of the following statements is correct?

Note: you are not required to have any context knowledge about the air quality index, apart from knowing it can take any value from 0 and above.

A randomised controlled trial was undertaken in a primary care setting to assess whether offering nicotine replacement therapy (NRT) sample kits would be more effective than standard care for patients who wanted to quit smoking.

The following 2-by-2 table was produced in jamovi and R:

Which of the following statements is correct?

A study investigated the length of stay in hospital (in days) for 202 people who had surgery at a hospital in Sydney.

The following summary statistics were computed.

• Mean: 6.5 days
• Median: 5 days
• Minimum: 1 day
• Maximum: 32 days
• 1st Quartile: 2 days
• 3rd Quartile: 9 days.
• Standard deviation: 6.2 days

Based on these summary statistics, which of the following is correct?

Suppose that in Winter, an estimated 5% of people in the community have a cold. What is the probability that in a lift full of 10 people, at least 1 person has a cold?

A randomised controlled trial was undertaken to examine the

effect of exercise on overall mortality in people with resected colon cancer

who had completed chemotherapy. 445 participants were randomised to receive a

structured excercise program, and 444 received general health-education

materials. The results of the trial are given below:

To compare to proportion of deaths in the group receiving

the structured exercise program to those receiving the general health education

materials, which would you calculate?

The weights of children who are five years old in a remote community are summarized in the following table.

Table: Weights of five-year old children

In which weight grouping does the median weight lie within?

Data on systolic blood pressure, along with smoking status and weight status, were collected from a sample of 500 adults. The data have been saved in the Datasets section of the Teams Home Page as:

Assessment data > Quizzes > Quiz0 - Practice > bloodpressure.rds

The dataset contains the following three variables:

• systolic_bp: Systolic blood pressure (mmHg)
• smoke: 1=smoker or 0=non-smoker
• overwt: 1=normal, 2=overweight, or 3=obese

What is the mean systolic blood pressure? Provide your answer with the appropriate number of decimal places for inclusion in a report to the Ministry of Health.