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In Exercises 1-8, find the percentage of data items in a normal distribution that lie a. below and b. above the given z-score. \(z=0.6\)

The government of a large city needs to determine whether the city's residents will support the construction of a new jail. The government decides to conduct a survey of a sample of the city's residents. Which one of the following procedures would be most appropriate for obtaining a sample of the city's residents? a. Survey a random sample of the employees and inmates at the old jail. b. Survey every fifth person who walks into City Hall on a given day. c. Survey a random sample of persons within each geographic region of the city. d. Survey the first 200 people listed in the city's telephone directory.

The city council of a large city needs to know whether its residents will support the building of three new schools. The council decides to conduct a survey of a sample of the city's residents. Which procedure would be most appropriate for obtaining a sample of the city's residents? a. Survey a random sample of teachers who live in the city. b. Survey 100 individuals who are randomly selected from a list of all people living in the state in which the city in question is located. c. Survey a random sample of persons within each neighborhood of the city. d. Survey every tenth person who enters City Hall on a randomly selected day.

A questionnaire was given to students in an introductory statistics class during the first week of the course. One question asked, "How stressed have you been in the last \(2 \frac{1}{2}\) weeks, on a scale of 0 to 10 , with 0 being not at all stressed and 10 being as stressed as possible?" The students' responses are shown in the frequency distribution. Use this frequency distribution to solve Exercises 3-6. $$ \begin{aligned} &\begin{array}{|c|c|} \hline \text { Stress Rating } & \text { Frequency } \\ \hline 0 & 2 \\ \hline 1 & 1 \\ \hline 2 & 3 \\ \hline 3 & 12 \\ \hline 4 & 16 \\ \hline 5 & 18 \\ \hline \end{array}\\\ &\begin{array}{|c|c|} \hline \text { Stress Rating } & \text { Frequency } \\ \hline 6 & 13 \\ \hline 7 & 31 \\ \hline 8 & 26 \\ \hline 9 & 15 \\ \hline 10 & 14 \\ \hline \text { Source Joumal of Personality and } \\ \hline \end{array}\\\ &\text { Social Psychology, 69, 1102-1112 } \end{aligned} $$ Which stress rating describes the greatest number of students? How many students responded with this rating?

The scores on a test are normally distributed with a mean of 100 and a standard deviation of 20. In Exercises 1-10, find the score that is \(1 \frac{1}{2}\) standard deviations above the mean.

In Exercises 1-8, find the percentage of data items in a normal distribution that lie a. below and b. above the given z-score. \(z=1.4\)

The scores on a test are normally distributed with a mean of 100 and a standard deviation of 20. In Exercises 1-10, find the score that is \(2 \frac{1}{2}\) standard deviations above the mean.

A questionnaire was given to students in an introductory statistics class during the first week of the course. One question asked, "How stressed have you been in the last \(2 \frac{1}{2}\) weeks, on a scale of 0 to 10 , with 0 being not at all stressed and 10 being as stressed as possible?" The students' responses are shown in the frequency distribution. Use this frequency distribution to solve Exercises 3-6. $$ \begin{aligned} &\begin{array}{|c|c|} \hline \text { Stress Rating } & \text { Frequency } \\ \hline 0 & 2 \\ \hline 1 & 1 \\ \hline 2 & 3 \\ \hline 3 & 12 \\ \hline 4 & 16 \\ \hline 5 & 18 \\ \hline \end{array}\\\ &\begin{array}{|c|c|} \hline \text { Stress Rating } & \text { Frequency } \\ \hline 6 & 13 \\ \hline 7 & 31 \\ \hline 8 & 26 \\ \hline 9 & 15 \\ \hline 10 & 14 \\ \hline \text { Source Joumal of Personality and } \\ \hline \end{array}\\\ &\text { Social Psychology, 69, 1102-1112 } \end{aligned} $$ How many students had a stress rating of 8 or more?

A random sample of 30 college students is selected. Each student is asked how much time he or she spent on homework during the previous week. The following times (in hours) are obtained: \(16,24,18,21,18,16,18,17,15,21,19,17,17,16,19,18,15,15\), \(20,17,15,17,24,19,16,20,16,19,18,17\). Construct a frequency distribution for the data.

In Exercises 1-8, find the percentage of data items in a normal distribution that lie a. below and b. above the given z-score. \(z=-1.8\)