Question

Give the correct notation for the mean. The average number of text messages sent in a day was 67 , in a sample of US smartphone users ages \(18-24\), according to a survey conducted by Experian. \(^{26}\)

Short answer

The correct notation for the mean is \(\bar{x} = 67\).

Step-by-step solution

Understanding Mean Notation

In statistics, the mean or the average is typically represented by different symbols. The most commonly used are \(\bar{x}\) or \(\mu\), where \(\bar{x}\) is usually used to denote the mean of a sample and \(\mu\) to denote the population mean.

Apply Correct Notation to Context

In the context of the problem, we are dealing with a sample (US smartphone users ages 18-24). Therefore, the appropriate symbol to use is \(\bar{x}\). And the given mean value is 67. Thus, the correct notation for the mean is \(\bar{x} = 67\).

Key concepts

Sample Mean

Understanding the concept of sample mean is fundamental in statistics, particularly when dealing with real-world data. It is the average obtained from a subset of the entire population, often used to make inferences about the population as a whole.

For example, in a survey conducted, if you collect data from a group of selected individuals, such as US smartphone users aged 18-24, and calculate the average number of text messages they send per day, you're computing the sample mean. Mathematically, the sample mean is represented using the symbol \( \bar{x} \), and it is calculated by summing up all the values in the sample and then dividing by the number of observations in that sample.

So if the average number of text messages sent in a day is 67, according to our survey, we can express this as \( \bar{x} = 67 \) where \( \bar{x} \) stands for the sample mean.

Population Mean

While the sample mean provides an average for a specific subset, the population mean (\( \mu \) ) represents the average of an entire population. It includes all individuals or items that meet certain criteria. Obtaining such a comprehensive measure is often impractical, which is why we resort to sampling.

In statistical notation, \( \mu \) is used when your data represents every single possible observation within the group you're studying. For instance, if we were able to survey every US smartphone user aged 18-24 about their text messaging habits, rather than just a sample, and calculated the average from that full data set, we'd be calculating the population mean, \( \mu \).

Statistical Symbols

Statistical symbols are the shorthand codes or pictograms that represent various statistical terms and concepts. Familiarity with these symbols is not only essential for interpreting data but also for communicating findings effectively.

Some of these symbols include \( \bar{x} \) for sample mean, \( \mu \) for population mean, \( \sigma^2 \) for population variance, and \( s^2 \) for sample variance. These symbols help condense complex formulas and data representations into manageable and universally understood notation. In the context of our example, \( \bar{x} \) is used as the appropriate symbol because we are dealing with a sample mean. Learning and understanding these symbols is critical for anyone studying or working with statistics.

Statistics Education

Statistics education equips students with the tools to collect, analyze, and interpret data, skills that are increasingly in demand in today's data-driven world. A solid foundation in statistics allows students to understand the distinction between sample and population means and the importance of correct notation.

To foster deep comprehension, educators focus on making these concepts accessible, often starting with hands-on activities and concrete examples that make abstract concepts more relatable. By using surveys, like the one in our exercise involving smartphone users, students can connect statistical theory with the real world, enhancing their appreciation for the discipline and its practical applications.