Which of the following best describes the relationship between the $standarddeviation$ and the $precision$ of a procedure?

Exit Velocity Use the frequency distribution whose class width is 4 obtained in Problem 25 in Section 2.2 to approximate the mean and standard deviation exit velocity. Compare these results to the actual mean and standard deviation exit velocity.

Travel Time Use the results of Problem 22 in Section 3.1 and Problem 22 in Section 3.2 to compute the z-scores for all the students. Compute the mean and standard deviation of these z-scores.

Answer the following based on the histograms shown in the next column.

a. Which measure of central tendency would you recommend reporting for the data whose histogram is shown in Figure I? Why? b. Which one has more dispersion? Explain.

[NW] [DATA] TelevisionsIn the Sullivan Statistics Survey I, individuals were asked to disclose the number of televisions in their household. In the following probability distribution, the random variable X represents the number of televisions in households.

d. Find the standard deviation of the random variable X.

If a distribution has zero variance, which of the following statements is true about the data values? $\mathrm{Var}\left(X\right)=0$

Suppose the birth weights of newborns in a population are normally distributed with a mean of $3.5$ kg and a standard deviation of $0.5$ kg. What is the z-score of a newborn who weighs $4$ kg?

In the context of displaying error bars on a graph, which quantity is most commonly used to represent the variability of the data?

Which formula should you use to calculate the variance and which formula should you use to calculate the standard deviation of a sample of $n$ observations $x_1$, $x_2$, ..., $x_n$?