STAT2103 CH1
Explain the difference between descriptive and inferential statistics.
Descriptive statistics describes sets of data. Inferential statistics draws conclusions about the sets of data based on sampling.
Are the data consisting of the classifications A, B, C, and D qualitiative or quantitative?
Qualitative, because they can only be classified into categories.
((((symmetric, skewed to the right, or skewed to the left? )))) The salaries of all persons employed by a large University
Skewed right because the mean value would be more than the median value
After the data are input as 1, 2, 3, or 4, are they qualitative or quantitative?
Qualitative, because they cannot be meaningfully added, subtracted, multiplied, or divided.
Explain the difference between qualitative and quantitative data.
Quantitative data are numerical in nature, while qualitative data are categorical in nature.
((((symmetric, skewed to the right, or skewed to the left?)))) The grades on an easy test
Skewed left because the mean value would be less than the median value
((((symmetric, skewed to the right, or skewed to the left?)))) The amounts of time students in your class studied last year
Symmetric because the mean value would be nearly the same as the median value
Explain how the relationship between the mean and median provides information about the symmetry or skewness of the data's distribution.
The mean is affected by extreme values, while the median is not. If the data set is skewed to the right, then the median is less than the mean. If the data set is symmetric, the mean equals the median. If the data set is skewed to the left, the mean is less than the median.
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Explain how populations and samples differ.
A population is a set of units of interest to a study. A sample is a subset of the units of a population.
Explain how populations and variables differ.
A population is a set of units of interest to a study. A variable is a characteristic or property of the units being studied.