Week 2 practice problems
12) Explain and give an example for each of the following types of variables: (a) equal-interval, (b) rank-order, (c) nominal, (d) ratio scale, (e) continuous?
Answers: (a) Equal-Interval: This scale has equal interval hence we can perform differences but does not have an absolute zero so we cannot perform division on these variables. These satisfaction levels of visitors (on Likert scale) on a scale of 1 to 5 this scale lies between rank order and ratio scale. (b) Rank-Order: These variables are in the next stage from the nominal. We can arrange them in rank order but cannot do any other statistical operation such as difference, multiplication or division. The education level: elementary school, high school, some college, and college graduate. (c) Nominal: We cannot perform any static operations on these variables. Gender: Male & Female (d) Ratio Scale: This scale has an absolute zero and we can perform all possible statistical operations on these variables. Like addition, difference, multiplication and division. Example: Temperature in Kelvin or age (e) Continuous: These variables have all possible values within the given range. For example weight or age. We can measure age on all possible points on the number line say between 0 to 100 years.
15) Following are the speeds of 40 cars clocked by radar on a particular road in a 35-mph zone on a particular afternoon:30, 36, 42, 36, 30, 52, 36, 34, 36, 33, 30, 32, 35, 32, 37, 34, 36, 31, 35, 20,24, 46, 23, 31, 32, 45, 34, 37, 28, 40, 34, 38, 40, 52, 31, 33, 15, 27, 36, 40 Make (a) a frequency table and (b) a histogram, and then (c) describe the general shape of the distribution. The lowest value is 15 and highest value is 52, so we make 7 classes with CI of 6.
19) Give an example of something having these distribution shapes: (a) bimodal, (b) approximately rectangular, and (c) positively skewed. Do not use an example given in this book or in class....
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