Chapter 2 - Measures of Location and Spread Flashcards
What are measures of location, and can you name some examples?
✯ Measures of location describe the central tendency of the data.
Examples include: Mean, Mode, Median
How do we calculate the xth percentile?
✯ Px = X times nth value/ 100
where P1 represents 1% in the data etc..
When dealing with discrete data, what are the two steps we take into account?
✯ Decimal Number? Round Up
✯ Whole Number? Take an average, with the next number.
When dealing with continuous data (grouped data), what are the three steps we take into account?
- Check for Gaps in Data
- Take the Exact Value
- Use Linear Interpolation
What assumption is made when using linear interpolation?
✯ When linear interpolation is used, we assume that the data values are evenly distributed within each class.
How do you go about linear interpolation?
- Find the cumulative frequency (can find sample size)
- Find the value of interest and its nth term as an exact value.
- Find which class interval this falls under.
- Create a diagram to find the data value of interest.
What are measures of spread? Name me examples too.
✯ How spread out the data is.
- Range
- Interquartile Range.
- Interpecentile Range (Pm-Pn)
- Variance
- Standard Deviation
What is the variance and standard deviation?
✯ Variance is a square measure
✯ Standard deviation is the square root of the variance
✯ The variance and standard deviation of a statistical data measures the average spread of the data values from its mean value.
How can we code data?
✯ Formula
y = x-a/b
Where x is the original data value.
What is the difference between coding measures of locations vs measure of spread?
✯ In general, a measure of location is affected by all operations, but a measure of spread is only affected by x and ÷
