Exam 7: Survey Sampling and Inference

Use the following information to answer the question. In a recent poll of 1100 randomly selected home delivery truck drivers, 26% said they had encountered an aggressive dog on the job at least once. -Report the 95% confidence interval for the proportion of all home delivery truck drivers who haveencountered an aggressive dog on the job at least once. (Round final calculations to the nearesttenth of a percent)

Which of the following statements is not true about a sampling distribution?

Suppose that in a recent poll of 900 adults between the ages of 35 and 45, 22% surveyed said theyhave thought about participating in an extreme sport such as bungee jumping. Find the 95%confidence interval for the proportion of adults ages 35 to 45 who have thought about participatingin an extreme sport such as bungee jumping then choose the correct interpretation. (Round to thenearest tenth of a percent)

Explain the difference between the standard error of a sample proportion and the marginof error of a confidence interval for a population proportion.

There are four colors in a bag containing 600 plastic chips. It is known that 34% of the chips areyellow. On average, how many chips from a random sample of 30 (with replacement) would beexpected to be yellow? Round to the nearest whole chip.

Use the following information to answer the question. An event planner does some research and finds that in the area wherea large children's event is to be held, approximately 1.75% of the children are lactose intolerant. Treat the 250 childrenexpected at the event as a simple random sample from the local population of about 100,000 children. -Suppose the event planner assumes that 2.8% of the children attending the event will belactose intolerant so he orders 7 lactose-free meals. What is the approximate probabilitythat more than 2.8% of the children attending the event are lactose intolerant and that he will not have enough lactose-free meals? Round to the nearest thousandth.

A random sample of 950 adult television viewers showed that 48% planned to watch sportingevent X. The margin of error is 4 percentage points with a 95% confidence. Does the confidenceinterval support the claim that the majority of adult television viewers plan to watch sporting eventX? Why?

Complete the statement by filling in the blank. When constructing a confidence interval, if the level of confidence increases the margin of error will_{--------------------} and the confidence interval will_{--------------------} Be . A larger sample size will improve the accuracy of the confidence interval, Therefore margin of error will_{--------------------} and the confidence interval will be _{--------------------}

A polling agency wants to determine the size of the random sample needed to estimate theproportion of voters who favor proposal X. The estimate should have a margin of error nomore than 4.5 percentage points at a 95% level of confidence. Determine the minimum sizeof the sample, rounding to the nearest whole person.

According to a snack cracker manufacturer, a batch of butter crackers has a defect rate of 8%. Suppose a quality inspector randomly inspects 500 crackers. Complete the following statement: The Quality inspector should expect _{--------------------}defective crackers, give or take _{--------------------} Crackers.

Researchers are interested in learning more about the age of women when they marry for the first time so they survey 500 married or divorced women and ask them how old they were when theyFirst married. The collection of the ages of the 500 women when they first Married is a _{--------------------}.

Explain the difference between a statistic and a parameter. Give an example of each.

Complete the statement by filling in the blank. When constructing a confidence interval, if the level of confidence increases the margin of error will_{--------------------} and the confidence interval be_{--------------------} . A larger sample size will improve the accuracy of the confidence interval, Therefore margin of error will _{--------------------}and the confidence interval will be_{--------------------}

Use the following information to answer the question. A marble manufacturer advertises that its bags of marbles will contain25% "milky-white" marbles. Suppose that a bag containing 80 marbles is inspected. -What is the margin of error, using a 95% confidence level, for estimating the trueproportion of adults who self-report that they cannot swim 24 yards? Round to the nearest thousandth.

A polling agency wants to determine the size of a random sample needed to estimate theproportion of homeowners who have an electronic home security system. The estimate should havemargin of error no more than 4 percentage points at a 95% level of confidence. Choose the mostconservative answer that is closest to your calculated number, rounding to the nearest wholeperson.

Use the following information to answer the question. In a recent poll of 1200 randomly selected adult office workers, 32% said they had worn a Halloween costume to the office at least once. -What is the margin of error, using a 95% confidence level, for estimating the true populationproportion of adult office workers who have worn a Halloween costume to the office at least once?(Round to the nearest thousandth)

Use the following information to answer the question. A marble manufacturer advertises that its bags of marbles will contain25% "milky-white" marbles. Suppose that a bag containing 80 marbles is inspected. -Use your answers to fill in the blanks: We expect_{--------------------} % milky-white marbles, give or take %_{--------------------}.

Use the following information to answer the question. A pescatarian is a person who eats fish and seafood but no otheranimal. An event planner does some research and finds that approximately 2.75% of the people in the area where a largeevent is to be held are pescatarian. Treat the 250 guests expected at the event as a simple random sample from the localpopulation of about 150,000. -Suppose the event planner assumes that 4% of the guests will be pescatarian so he orders 10 pescatarian meals. What is the approximate probability that more than 4% of the guests are Pescatarian and that he will not have enough pescatarian meals? Round to the nearest thousandth.

Which of the following statements is not true about a sampling distribution?

Use the following information to answer the question. A pollotarian is a person who eats poultry but no red meat. A wedding planner does some research and finds that approximately 3.5% of the people in the area where a large wedding is to be held are pollotarian. Treat the 300 guests expected at the wedding as a simple random sample from the local population of about 200,000. -Suppose the wedding planner assumes that 5% of the guests will be pollotarian so she orders 15pollotarian meals. What is the approximate probability that more than 5% of the guests arepollotarian and therefore she willnot have enoughpollotarian meals? Round to the nearestthousandth.