Exam 1: Introduction to Statistics

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.

In a cross-sectional study, data are _____________.

Explain why using self-reported data instead of measured data is a potential pitfall in data collection. Be sure to include an example.

At a school there are two different math classes for children of the same age. have different teachers. The school principal is interested in gauging the effectiveness of two different teaching methods and asks each teacher to try one of the methods. At the end of the semester both classes are given the same test and the results are compared. In this experiment, what is the variable of interest? Give some examples of variables which could be confounding variables.

A coach uses a new technique in training middle distance runners. The times, in seconds, for 8 different athletes to run 800 meters before and after this training are shown below. Athlete Before 115.2 114 116.4 119.8 110.9 112.4 111.5 117.3 After 112.9 112.7 114 120.6 109.1 109.1 107.9 113.4 Does the conclusion that the technique is effective appear to be supported with statistical significance? Does the conclusion that the technique is effective appear to have practical significance?

"38% of adults in the United States regularly visit a doctor". This conclusion was reached by a college student after she had questioned 520 randomly selected members of her college. What is wrong with her conclusion?

A _______________ is the collection of data from every member of the population.

A lawyer surveyed a simple random sample of his colleagues and asked them whether they were left-handed or right-handed. Is this convenience sample likely to provide results typical of all adults in the United States? Do convenience samples in general provide good results?

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

Determine which level of measurement is appropriate. A sample of children's balls are classified from softest to hardest.

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

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?

The good design of experiments includes blinding, _____________, and __________________.

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

Researchers collect data by interviewing athletes who have won Olympic gold medals from 1992 to 2016. Identify the type of study.

Which type of experiment separates subjects into groups that are similar but differ in ways that might affect the outcome of the experiment?

Identify the sample and population. Also, determine whether the sample is likely to be representative of the population. A study is interested in whether men and women are equally likely to vote Democratic, Republican or Independent or not vote in a presidential election. Results were polled through a popular news website.

Identify which type of sampling is used. To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day.

A psychology student wishes to investigate differences in political opinions between business majors and political science majors at her college. She randomly selects 100 students from the 260 business majors and 100 students from the 180 political science majors. Does this Sampling plan result in a random sample? Simple random sample? Explain.

Determine whether the given value is a statistic or a parameter. After taking the first exam, 15 of the students dropped the class.