Exam 1: Introduction to Statistics

Determine whether the given value is a statistic or a parameter. Thirty percent of all dog owners poop scoop after their dog.

A teacher was interested in knowing how much tax people pay in the United States. She selected a simple random sample of her friends and asked them about their taxes. Is this sample likely to be representative of all adults in the United States?

Determine whether the given value is from a discrete or continuous data set. The time it takes a computer to complete a task.

Correlation does not imply ________.

An employee at the local ice cream parlor asks three customers if they like chocolate ice cream.

Explain what is meant by the term "confounding," and give an example of an experiment in which confounding is likely to be a problem.

Explain the difference between stratified and cluster sampling.

A tax auditor selects every 1000th income tax return that is received. Identify which of these types of sampling is used.

In a poll of 50,000 randomly selected college students, 74% answered "yes" when asked "Do you have a television in your dorm room?".

A management survey for a company surveyed 235 employees. 44.7% of the employees surveyed were females. The number of males would be ________.

Charlie's teacher claims that he does not study and just guesses on exams. On an exam with 201 true-false questions, Charlie answered 53.7% of the questions correctly. Calculations using these results show that if he were really just guessing, there would be roughly 1 chance in 7 that he would do this well. Is there statistically significant evidence against the teacher's claim that Charlie is just guessing? Why or why not?

A sample of fish is taken from a lake to measure the effect of pollution from a nearby factory on the fish.

After inspecting all of 55,000 kg of meat stored at the Wurst Sausage Company, it was found that 45,000 kg of the meat was spoiled.

Use critical thinking to develop an alternative conclusion. A study shows that the number of reported sexually transmitted diseases was significantly higher for high schools that offered courses in sex education than for high schools that did not. Conclusion: The introduction of sex education courses at the high school level has resulted in increased promiscuity among teens.

Determine whether the given description corresponds to an observational study or an experiment. A doctor gives a new medication to half of his patients with the flu and a placebo to the other half of his patients with the Flu)

Identify which of these types of sampling is used: random, stratified, systematic, cluster, convenience. -A tax auditor selects every 1000th income tax return that is received.

Provide an appropriate response. -A computer company employs 100 software engineers and 100 hardware engineers. The personnel manager randomly selects 20 of the software engineers and 20 of the hardware engineers and questions them about Career opportunities within the company. Does this sampling plan result in a random sample? Simple random Sample? Explain.

Last year, the average math SAT score for students at one school was 475. The headmaster introduced new teaching methods hoping to improve scores. This year, the mean math SAT score for a sample of students was 481. Is there statistically significant evidence that the new teaching method is effective? If the teaching method had no effect, there would be roughly a 3 in 10 chance of seeing such an increase. Does the result have statistical significance? Why or why not? Does the result have practical significance?

Determine whether the given description corresponds to an observational study or an experiment. A political pollster reports that his candidate has a 10% lead in the polls with 10% undecided.

What type of data values are quantitative and the number of values is finite or countable?