Short Quiz on BIOSTATISTICS- Introduction, Measure of central tendency
Instruction
2. There is 1 Mark for each correct Answer
Dichotomous scale
Nominal scale
Ordinal scale
A researcher selected all possible samples from a population and plotted their means on a line graph. This distribution is called
Sample distribution
Sampling distribution
Population distribution
Parametric distribution
Which of the following is true regarding the following image?
Mean = Median = Mode
Mean = Median, not equal to Mode
Mean = Mode, not equal to Median
Mean, Median and Mode are not equal
A study was conducted to find out number of positive lymph nodes in a population of breast cancer patients who underwent axillary dissection. A graph was plotted between the number and frequency of positive nodes as below. Which of the following is the correct statement?
A; Mode B: Median C: Mean
A: Mode B: Mean C: Median
A: Median B: Mode C: Mean
A: Mean B: Median C: Mode
The values of systolic BP in a given data are 120, 120, 130, 120, 110, 110, 200. Which of the following will be best to use for central tendency in the given data?
Mean
Median
Mode
Harmonic mean
Mean and standard deviation can be worked out only if data is on –
Ans. is \’a\’ i.e., Interval/Ratio scale
It is the arithmetic average of the individual values divided by the number of variables.
Thus quite logically, mean is useful only for quantitative variables (ie Interval and Ratio Scale data) which have got a measurable attribute.
o Standard Deviation
It\’s the measure of variance, calculated by method which everyone of us are well aware. It first involves findings out the mean value. Thus SD can only be worked out for quantitative data (Interval and ratio scales). o Now lets see other measures of central tendency and measures of variation.
Ans: B. Sampling distribution
Sampling distribution / finite-sample distribution:
- The probability distribution of a given statistic based on a random sample.
- They allow analytical considerations to be based on the sampling distribution of a statistic, rather than on the joint probability distribution of all the individual sample values.
Ans: B. Mean = Median, not equal to Mode
- Redline indicates normal distribution hence Mean = Median
- Blueline indicates bimodal distribution hence 2 Modes.
- So Mean = Median but not equal to Mode
Ans: A. A; Mode B: Median C: Mean
(Ref Park 23/e p847, 24/e p884)
| Distribution | Central Tendency |
| Normal (Gaussian) Distribution | Mean = Median = Mode° |
| Right (Positive) Skew Distribution | Mean >Median >Mode° |
| Left (Negative) Skew Distribution | Mean |
The values of systolic BP in a given data are 120, 120, 130, 120, 110, 110, 200. Which of the following will be best to use for central tendency in the given data?
Ans.A. Mean
Arithmetic mean
- It is the most commonly used statistical average.
- To calculate the mean, add up the values of all individual observations and then divide by the number of observations.
- The process of adding together is called summation and is denoted by the sign E or S.