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.