Identify at least one potential source of bias in the following studies. Explain why the bias would or would not affect your view of the study.

Based on a survey of $2718$ people, the National Opinion Research Center concluded that $32 \%$ of Americans always make a special effort to sort and recycle glass, cans, plastic, or papers. Twenty-four percent of Americans often make such an effort.

Cancer Research. A seven-year medical research study reported that women whose mothers took the drug DES during pregnancy were twice as likely to develop tissue abnormalities that might lead to cancer as were women whose mothers did not take the drug.

e. Medical studies often use a relatively large sample (in this case, 3,980 ). Why?

Explain why you cannot use the methods of this section to find the following probability.

A university is concerned about the academic standing of its intercollegiate athletes. A study committee chooses an SRS of 50 of the 316 athletes to interview in detail. Suppose that in fact 40% of the athletes have been told by coaches to neglect their studies on at least one occasion. What is the probability that at least 15 in the sample are among this group?

Cost of Massage Therapy Sessions. The Wall Street Journal reported on several studies that show massage therapy has a variety of health benefits and it is not too expensive. A sample of 10 typical one-hour massage therapy sessions showed an average charge of $\$ 59$. The population standard deviation for a one-hour session is $\sigma=\$ 5.50$.

b. Using $95 \%$ confidence, what is the margin of error?

For each of the items below, triple underline any lowercase letter that should be capitalized. Then, put a slash mark through any uppercase letter that should not be capitalized.

Example 1. My $\cancel{\text{A}}$unt Bertha worked for the $\underset{ \underset{\_}{\_}}{}$ red $\underset{ \underset{\_}{\_}}{}$ cross for many years.

13. Most Juniors take English, social studies III, and a course in Science.

Trichothiodystrophy is a human inherited disorder characterized by premature aging, including osteoporosis, osteosclerosis, early graying, infertility, and reduced life span. The results of studies showed that the mutation that causes this disorder occurs in a gene that encodes a DNA helicase. Propose a mechanism for how a mutation in a DNA helicase might cause premature aging. Be sure to relate the symptoms of the disorder to possible functions of the helicase enzyme.

The director of graduate studies at a large college of business has the objective of predicting the grade point average (GPA) of students in an MBA program. The director begins by using the Graduate Management Admission Test (GMAT) score. A sample of 20 students who have completed two years in the program is selected and stored in GPIGMAT.

Perform a residual analysis on your results and evaluate the regression assumptions.

When Lux studies her psychology terms, she tries to tie each concept into something she already knows. She thinks about the meaning of the concept rather than just saying the words over and over. Which of the following best explains Lux's approach to encoding memories? a. information-processing model b. levels-of-processing model c. selective attention d. maintenance rehearsal

The columns in Table 11.37 contain the Race/Ethnicity of U.S. Public Schools for a recent year, the percentages for the Advanced Placement Examinee Population for that class, and the Overall Student Population. Suppose the right column contains the result of a survey of 1,000 local students from that year who took an AP Exam. Perform a goodness-of-fit test to determine whether the local results follow the distribution of the U.S. overall student population based on ethnicity. $$ \begin{matrix} \text{Race/Ethnicity} & \text{AP Examinee Population} & \text{Overall Student Population} & \text{Survey Frequency}\\ \text{Asian, Asian American, or Pacific Islander} & \text{10.2\\%} & \text{5.4\\%} & \text{113}\\ \text{Black or African-American} & \text{8.2\\%} & \text{14.5\\%} & \text{94}\\ \text{Hispanic or Latino} & \text{15.5\\%} & \text{15.9\\%} & \text{136}\\ \text{American Indian or Alaska Native} & \text{0.6\\%} & \text{1.2\\%} & \text{10}\\ \text{White} & \text{59.4\\%} & \text{61.6\\%} & \text{604}\\ \text{Not reported/other} & \text{6.1\\%} & \text{1.4\\%} & \text{43}\\ \text{Table 11.37}\\ \end{matrix} $$

Studies show that the concentration of PCBs is much higher in malignant breast tissue than in normal breast tissue. If a study of 50 women with breast cancer reveals an average PCB concentration of $22.8 \times 10^{-4} \operatorname{gram},$ with a standard deviation of $4.8 \times 10^{-4} \mathrm{gram},$ is the mean concentration of PCBs less than $24 \times 10^{-4} \text { gram? }$

Many medical studies have tried to prove that smoking causes lung cancer.

a. Is smoking a necessary condition for lung cancer? Why or why not?

b. Is smoking a sufficient condition for lung cancer? Why or why not?

c. Is there a correlation between people who smoke and people who get lung cancer? Explain your reasoning.

d. Is it true that smoking causes lung cancer? If so, how was it proven?

In preliminary design studies for a sun-powered car, it is estimated that the mass of the car and driver will be $100 \mathrm{~kg}$ and the torque produced by the engine will result in a $60-\mathrm{N}$ tangential force on the car. Suppose that the car starts from rest on the track at $A$ and is subjected to a constant 60-N tangential force. Determine the magnitude of the car's velocity and the normal component of force on the car when it reaches $B$.

For each of the following studies, describe a possible source of bias. Explain the likely direction of the bias. A flour company wants to know what percent of local households bake at least twice a week. A company representative calls 500 randomly selected households during the daytime and finds that 156 of the 312 people who responded bake at least twice a week.

The number of small business loans awarded to minority-owned businesses in 2007 is given in the table. What is the probability that a randomly selected small business loan awarded to a minority-owned business in 2007 was awarded to a Hispanic-American small business?

$$\left[\begin{array}{l|l} \text{Minority Group} & \text{Number of Loans} \\ \hline \text{African American} & 6,632\\ \hline \text{Asian American} & 13.455\\ \hline \text{Hispanic American} & 8,795\\ \hline \text{Native American} & 835 \end{array}\right]$$