Cybersecurity survey. Refer to the State of Cybersecurity (2015) survey of firms from around the world, Exercise $1.20$ (p. 26). Recall that of the 766 firms that responded to the survey, 628 (or $82 \%$ ) expect to experience a cyberattack (e.g., a Malware, hacking, or phishing attack) during the year. Estimate the probability of an expected cyberattack at a firm during the year with a $90 \%$ confidence interval. Explain how $90 \%$ is used as a measure of reliability for the interval.

In the first stage of corporate citizenship:

a. the company must learn how to tackle the problem and make the new policy work.

b. managers are uninterested and uninvolved with social issues.

c. supervisors and managers become familiar with new routines that are necessary to cope with a social problem.

d. a company must institutionalize its new social policy and make it a part of standard operating procedures.

You are updating the operating system on your iPad. Your iPad is connected to your computer and you are using iTunes to install the update. What would happen to your iPad if you disconnect it before the operating system update is complete?

An organization’s ________________________________________ assembles its disaster recovery team.

Disaggregation of annually reported accounting data. Researchers have constructed a new measure of disclosure quality-called disaggregation quality $(D Q)$-based on the level of disaggregation of financial data items in a firm's annual reports (Journal of Accounting Research, December 2015). Quantitative DQ values were computed for each of 125,873 firms that had annual balance sheet data from 1973 to 2011 reported on Compustat. One objective is to describe the distribution of the DQ values for firms reported on Compustat. What is the experimental unit for this study?

Nannies who are INA certified. The International Nanny Association (INA) reports that in a sample of 928 inhome child care providers (nannies), 128 have passed the INA Nanny Credential Exam (2014 International Nanny Association Salary and Benefits Survey). Use Wilson's adjustment to find a $95 \%$ confidence interval for the true proportion of all nannies who have passed the INA certification exam.

Use the applet Confidence Intervals for a Mean (the impact of not knowing the standard deviation) to compare proportions of $z$-intervals and $t$-intervals that contain the mean for a population with a skewed distribution. How does skewedness of the underlying distribution affect the proportions of $z$-intervals and $t$-intervals that contain the mean?

A random sample of 90 observations produced a mean

$$\overline { x } = 25.9$$

and a standard deviation s = 2.7. Find a 99% confidence interval for

$$\mu$$

Use the applet Confidence Intervals for a Mean (the impact of not knowing the standard deviation) to compare proportions of $z$-intervals and $t$-intervals that contain the mean for a population with a skewed distribution. Describe any patterns you observe between the proportion of $z$-intervals that contain the mean and the proportion of $t$-intervals that contain the mean as the sample size increases.

A random sample of 90 observations produced a mean $\bar{x}=25.9$ and a standard deviation $s=2.7$.Find an approximate $90 \%$ confidence interval for $\mu$

Which of the following statements about a controlled experiment is true? a. All the variables must be kept the same. b. Only one variable is tested at a time. c. Scientists always use controlled experiments. d. Controlled experiments cannot be performed on living things.

Use the applet Confidence Intervals for a Mean (the impact of not knowing the standard deviation) to compare proportions of $z$-intervals and $t$-intervals that contain the mean for a population with a skewed distribution. Repeat part a first for $n=10$ and then for $n=20$. Compare your results with those in part a.

Use the applet Confidence Intervals for a Mean (the impact of not knowing the standard deviation) to compare proportions of $z$-intervals and $t$-intervals that contain the mean for a population with a skewed distribution. Using $n=5$ and the right skewed distribution with mean 50 and standard deviation 10 , run the applet several times. How do the proportions of $z$-intervals and $t$-intervals that contain the mean compare?

A random sample of 90 observations produced a mean

$$\overline { x } = 25.9$$

and a standard deviation s = 2.7. Find a 95% confidence interval for the population mean

$$\mu$$