In a survey of a group of men, the heights in the 20 - 29 age group were normally distributed, with a mean of 67.4 inches and a standard deviation of 3.0 inches. A study participant is randomly selected. Complete parts (a) through (d) below. (a) Find the probability that a study participant has a height that is less than 67 inches. The probability that the study participant selected at random is less than 67 inches tall is (b) Find the probability that a study participant has a height that is between 67 and 70 inches. The probability that the study participant selected at random is between 67 and 70 inches tall is \( \square \). (Round to four decimal places as needed.) (c) Find the probability that a study participant has a height that is more than 70 inches. The probability that the study participant selected at random is more than 70 inches tall is \( \square \). (Round to four decimal places as needed.) (d) Identify any unusual events. Explain your reasoning. Choose the correct answer below. A. The events in parts (a), (b), and (c) are unusual because all of their probabilities are less than 0.05 . The events in parts (a) and (c) are unusual because its probabilities are less than 0.05 . C. There are no unusual events because all the probabilities are greater than 0.05. D. The event in part (a) is unusual because its probability is less than 0.05 .

The annual rainfall in a certain region is approximately normally distributed with mean 42.6 inches and standard deviation 5.7 inches. Round answers to the nearest tenth of a percent. a) What percentage of years will have an annual rainfall of less than 44 inches? b) What percentage of years will have an annual rainfall of more than 40 inches? c) What percentage of years will have an annual rainfall of between 39 inches and 43 inches? Question Help: \( \quad \) Read Video

A random sample of 69 produced the summary statistics \( \bar{x}=0.326 \) and \( s^{2}=0.064 \). Complete parts a and \( b \). State and interpret the results of the test. A. Reject \( H_{0} \). There is insufficient evidence to indicate that the true population mean is less than 0.37 at \( \alpha=0.10 \). Bo not reject \( H_{0} \). There is sufficient evidence to indicate that the true population mean is less than 0.37 at \( \alpha=0.10 \). C. Reject \( H_{0} \). There is sufficient evidence to indicate that the true population mean is less than 0.37 at \( \alpha=0.10 \). Do not reject \( H_{0} \). Thefe is insufficient evidence to indicate that the true population mean is less than 0.37 at \( \alpha=0.10 \).

A variable \( x \) is normally distributed with mean 21 and standard deviation 8 . Round your answers to the nearest hundredth as needed. a) Determine the \( z \)-score for \( x=27 \). \[ z=0.75 \] b) Determine the \( z \)-score for \( x=16 \). \[ z= \]

University researchers published a working paper. One of the objectives of the study was to determine whether ride-share drivers actually make a profit. Data collected from a sample of 1,126 ride-share drivers yielded a mean monthly profit \( \bar{x}=\$ 661 \) with standard deviation \( s=\$ 581 \). A ride-share company executive reports that \( \mu \), the true mean monthly profit of all its rideshare drivers, is \( \$ 1,000 \). Use \( \alpha=0.01 \) to test the executive's figure. Complete parts a through e below. b. Find the rejection region for the test. Select the correct choice below and fill in the answer box(es) within your choice. (Round to two decimal places as needed.) A. \( z \) < \( z>\square \) C. \( z<\square \) or \( z>\square \)

\( 1 \leftarrow \begin{array}{l}\text { Researchers conducted a study on using a chief executive officer's facial structure to predict a firm's financial } \\ \text { performance. The facial width-to-height ratio (WHR) for each in a sample of } 52 \text { CEOs at publicly traded firms was } \\ \text { determined. The sample resulted in } \bar{x}=1.55 \text { and } s=0.36 \text {. An analyst wants to predict the financial performance of a } \\ \text { firm based on the value of the true mean facial WHR of CEOs. The analyst wants to use the value of } \mu=2.1 \text {. Do yo } \\ \text { recommend he use this value? Conduct a test of hypothesis for } \mu \text { to help you answer the question. Specify all the } \\ \text { elements of the test, including } H_{0}, H_{a} \text {, test statistic, } p \text {-value, and your conclusion. Test at } \alpha=0.01 \text {. } \\ \text { What is the value of the test statistic? } \\ z=-11.02 \text { (Round to two decimal places as needed.) } \\ \text { Find the p-value. } \\ \text { p-value }=\square \text { (Round to three decimal places as needed.) }\end{array} \).