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1.2: The Nature of Data

CHS Statistics. 1.2: The Nature of Data. Objective: To understand the different types of data. Data. Data ( plural ) – observations (such as measurements, genders, and survey responses) that have been collected Datum ( singular )

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1.2: The Nature of Data

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  1. CHS Statistics 1.2: The Nature of Data Objective: To understand the different types of data

  2. Data • Data (plural)– observations (such as measurements, genders, and survey responses) that have been collected • Datum (singular) • Sometimes used to find statistics if the context of the data is randomly selected and/or representative of the population

  3. Parameter vs. Statistic • Parameter – a numerical measurement describing some characteristic of a population • Statistic – a numerical measurement describing some characteristic of a sample

  4. Parameter vs. Statistic – YOU DECIDE! • A recent survey of a sample of MBAs reported that the average salary for an employee with an MBA is more than $82,000. • Starting salaries for the 667 MBA graduates for the University Of Chicago Graduate School Of Business increased 8.5% from the previous year. • In a random check of a sample of retail stores, the Food and Drug Administration found that 34% of the stores were not storing fish at the proper temperature. • When Lincoln was first elected to the presidency, he received 39.82% of the 1,865,908 votes cast.

  5. Two Types of Data • Quantitative Data – values that answer questions about the quantity or amount (with units) of what is being measured. • Examples: income ($), height (inches), weight (pounds) • Categorical Data – (qualitative data) can be separated into different categories that are often distinguished by some nonnumeric characteristic • Examples: sex, race, ethnicity, zip codes • Wait? Hold up! Did I just see a zip codes as categorical data? I thought they were numbers…

  6. Categorical vs. Quantitative - You Decide! • Length of a song • Responses in an opinion poll • Telephone Number • Income of college graduates • The genders (male/female) of college graduates

  7. Discrete vs. Continuous Data • Discrete Data– result when a number of possible values is either a finite number or a “countable” number (dealing with counts) • Example: the number of students with blonde hair • Continuous Data – result from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions, or jumps (often times has units of measure attached) • Example: the amount of rainfall in Zelienople this past month

  8. Discrete vs. Continuous Data – YOU DECIDE! • X represents the number of motorcycle accidents in one year in California. • x represents the length of time it takes to get to work. • x represents the volume of blood drawn for a blood test. • x represents the number of rainy days in the month of July in Orlando, Florida. • x represents the amount of snow (in inches) that fell in Nome, Alaska last winter.

  9. Levels of Measurement • Nominal – characterized by data that consist of names, labels, or categories only • The data cannot be arranged in an ordering scheme (such as high to low) • Example: survey responses of yes, no, and undecided • Ordinal – can be arranged in some order, but the differences between the data values either cannot be determined or are meaningless • Example: grade letters (A, B, C, D, F); movie ratings (1, 2, 3, 4, 5) – while you can find the difference between the ratings, it is meaningless. The difference of 1 or 2 is meaningless, because it cannot be compared to other similar differences.

  10. Levels of Measurement (continued) • Interval – similar to the ordinal level, but the difference between any two data values is meaningful. However, there is no natural zero starting point (where none of the quantity is present). • Example: temperatures (while 0° F seems like a good starting point, it isn't necessarily) • Ratio –similar to the interval, but has a natural zero starting point (where zero indicates none of the quantity is present) • Differences and ratios are meaningful • Example: weights of adult humans, prices of jeans

  11. Levels of Measurement – YOU DECIDE! • Body temperature in degrees Fahrenheit of a swimmer • Collection of phone numbers • Final standing for the football Northeastern Conference • Heart rate (beats per minute) of an athlete.

  12. 1.2 Assignment P. 10 #1 – 19 ALL

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