Exam 1: Introduction to Statistics

Form a conclusion about statistical significance. Do not make any formal calculations. Either_ use the results provided or make subjective judgments about the results. 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 which of the four levels of measurement is most appropriate. Students' grades, A, B, or C, on a test.

Identify which type of sampling is used. The name of each contestant is written on a separate_ card, the cards are placed in a bag, and three names are picked from the bag.

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

Why do you think that cluster sampling is frequently used in practice?_

Identify which type of sampling is used. A research team wants to study the demographics of college students in the U.S. using proportionate samples of students in majors reflecting actual U.S. percentages.

Determine which of the four levels of measurement is most appropriate. Level of satisfaction of survey respondents.

A _______________

Subscribers of the women's magazine Cosmopolitan are asked to participate in a survey about_ preferred cereals for breakfast. Are the results likely to be representative of all women? Of all subscribers of Cosmopolitan? Why or why not?

In a cross-sectional study, data are _____________.

Identify which type of sampling is used._ numbers, then interviews the voters corresponding to those numbers.

Would an observational study or an experiment be more appropriate to investigate the effects on humans of a substance known to be toxic? Explain.

A gardener has 75 clients, 45% of whom are businesses. Find the number of business clients.

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

Identify the sample and population. Also, determine whether the sample is likely to be representative of the population. An employee at the local ice cream parlor asks three customers if they like chocolate ice cream.

Which of the following does not apply to the ratio level of measurement?

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

A teacher was interested in knowing how much tax people pay in the United States. 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?

A ______________ is the complete collection of all measurements or data collected, whereas, a _____________ is a subcollection of members selected from the complete collection.

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