Who prepares your tax return? Refer to the Behavioral Research and Accounting (January 2015) study on income tax compliance, Exercise $5.50$ (p. 297). Recall that in a sample of 270 U.S. adult workers, the researchers found that $37 \%$ prepare their own tax return. Construct a $99 \%$ confidence interval for the true proportion of all U.S. adult workers who prepare their own tax return.

Who prepares your tax return? Refer to the Behavioral Research and Accounting (January 2015) study on income tax compliance, Exercise $5.50$ (p. 297). Recall that in a sample of 270 U.S. adult workers, the researchers found that $37 \%$ prepare their own tax return. According to the researchers, about $70 \%$ of the sampled workers were recruited from a shopping mall (where they were reimbursed $\$ 5$ for their time) and about $30 \%$ were full-time workers enrolled in a professional graduate degree program. How might this information impact the inference you made in part $\mathbf{b}$ ?

It costs you $10 to draw a sample of size n = 1 and measure the attribute of interest. You have a budget of$1,200. a. Do you have sufficient funds to estimate the population mean for the attribute of interest with a 95% confidence interval 4 units in width? Assume that

$$\sigma = 12$$

b. If a 90% confidence level were used, would your answer to part a change? Explain.

In each case, find the approximate sample size required to construct a 95% confidence interval for p that has sampling error SE = .06. a. Assume that p is near .3. b. Assume that you have no prior knowledge about p , but you wish to be certain that your sample is large enough to achieve the specified accuracy for the estimate.

U.S. Postal Service's performance. The U.S. Postal Service (USPS) reports that $95 \%$ of first-class mail within the same city is delivered on time (i.e., within 2 days of the time of mailing). To gauge the USPS performance, Price Waterhouse monitored the delivery of first-class mail items between Dec. 10 and Mar. 3-the most difficult delivery season due to bad weather conditions and holidays. In a sample of 332,000 items, Price Waterhouse determined that 282,200 were delivered on time. Comment on the performance of USPS first-class mail service over this time period.

Cable TV subscriptions and "cord cutters." Refer to the Pew Research Center Survey (December 2015) on cable TV subscriptions, Exercise $2.4$ (p. 48). In a sample of 2,001 U.S. adults, 1,521 reported that they currently receive cable or satellite TV service at home, 180 revealed that they have never subscribed to cable/satellite TV service at home, and 300 admitted that they are "cord cutters," i.e., they canceled the cable/satellite TV service. One of the surveyed adults is randomly selected and his or her cable TV subscription status is determined. List the sample points for this study.

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.

Find the reference number for each value of t. $t=-\frac{7 \pi}{6}$

A car has wheels of radius 30 cm. The car starts from rest and accelerates uniformly to a speed of 15 m/s in a time of 8.0 s. a) Find the angular acceleration of the wheels. b) Find the number of rotations a wheel makes during the time the car is accelerating.

A circular object begins from rest and rolls without slipping down an incline, through a vertical distance of $4.0 \mathrm{~m}$. When the object reaches the bottom, its translational velocity is $7.0 \mathrm{~m} / \mathrm{s}$. What is the constant $c$ relating the moment of inertia to the mass and radius (see equation 10.11) of this object? a) $0.80$, b) $0.60$, c) $0.40$, d) $0.20$.

The sports car starts from rest and travels along a straight road. Its initial increasing acceleration is caused by the rear wheels of the car as shown on the graph. Construct the $v-s$ graph. What is the velocity of the car when $s=10 \mathrm{~m}$ and $s=15 \mathrm{~m}$ ?

A rigid rod of mass $m_3$ is pivoted at point $A$, and masses $m_1$ and $m_2$ are hanging from it. b) What is the ratio of $L_1$ to $L_2$, where these are the distances from the pivot point to $m_1$ and $m_2$, respectively? The ratio of the weights of $m_1, m_2$, and $m_3$ is $1: 2: 3$.

Consider a string with a linear mass density of $0.1747 \mathrm{~g} / \mathrm{cm}$, which is oscillating as shown in the figure. The string is under a tension of $10.81 \mathrm{~N}$ and is vibrating at a frequency of $59.47 \mathrm{~Hz}$. What is the length of the string?

In the movie Superman, Lois Lane falls from a building and is caught by the diving superhero. Assuming that Lois, with a mass of $50.0 \mathrm{~kg}$, is falling at a terminal velocity of $60.0 \mathrm{~m} / \mathrm{s}$, how much force does Superman exert on her if it takes $0.100 \mathrm{~s}$ to slow her to a stop? If Lois can withstand a maximum acceleration of $7 g$ s, what minimum time should it take Superman to stop her after he begins to slow her down?