Biostatistics & Research · patient case question
For the scores 64, 56, 48, 66 and 66, what are the median and the mean respectively?
Patient case: Reading the evidence
demo: Journal club
chief: The practice is reviewing published evidence before making a purchasing decision and interpreting a set of student examination results.
history: Five dental students scored 64, 56, 48, 66 and 66 on an examination. A trial reports three laser devices, each with a mean difference and a 95 percent confidence interval. A separate paper reports a diagnostic test's performance.
meds: Not applicable.
findings: Laser 1: confidence interval crossing zero into negative values, lowest price. Laser 2, an erbium YAG device: confidence interval entirely above zero, mid price. Laser 3: confidence interval crossing zero, highest price.
Show answer and explanation
Correct answer: D. 64 and 60
- A. 66 is the mode, the most frequently occurring value, not the median.
- B. The median of 64 is right but the mean is 60, not 68.
- C. This reverses the two statistics.
- D. Correct. Sorting the values gives 48, 56, 64, 66, 66, so the middle value and therefore the median is 64. The sum is 300 and dividing by 5 gives a mean of 60. Note the order in which the question asks for them; reversing the two is the commonest error on this item.
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