chapter 5

Based solely on the information​ given, do you have reason to question the results of the following hypothetical​ study? Explain your reasoning. A study of the academic preparation of high school language arts teachers used the​ teachers' mathematics scores on a standardized test for data. Is there reason to question the​ results? Select all that apply.

-​​Yes, there is reason. The variables that were measured are not identified. -Yes, there is reason. The study was about the preparation of language arts​ teachers, but uses the​ teachers' mathematics scores. ​-Yes, there is reason. Scores on standardized tests do not necessarily predict preparation.

What is​ bias? How can it affect a statistical​ study?

Bias refers to any problem in the design or conduct of a statistical study that tends to favor certain results.Bi

Decide whether the following statement makes sense​ (or is clearly​ true) or does not make sense​ (or is clearly​ false). Explain your reasoning. I found a nearly perfect positive correlation between variable A and variable B and therefore was able to conclude that an increase in variable A causes an increase in variable B.

The statement does not make sense because a correlation alone is not enough evidence to establish causality.

Decide whether the following statement makes sense​ (or is clearly​ true) or does not make sense​ (or is clearly​ false). Explain your reasoning. I wanted to test the effects of vitamin C on​ colds, so I gave the treatment group vitamin C and gave the control group vitamin D.

The statement does not make sense. The control group should only receive a​ placebo, not another treatment.

Which team in a football league has the linemen with the greatest average​ weight?

Observational study

A recent telephone poll of 995 randomly selected men revealed that 5 in 10 men believe there has been progress in finding a cure for cancer in the last 35 years. Describe the​ population, sample, population​ parameters, and sample statistics.

The Th 995 men selected

Consider an experiment designed to determine the effectiveness of a new drug. The drug is given to participants in the treatment​ group, while participants in the control group receive a placebo. For the set of results​ described, discuss whether there appears to be evidence that the treatment is effective. 21​% of those in the treatment group showed​ improvement; 67​% of those in the placebo group showed improvement. Is there good evidence that the treatment is​ effective?

no

Consider the hypothetical study described below. Based solely on the information​ given, do you have reason to question the results of the​ study? Explain your reasoning. Researchers design five survey questions to determine whether Norwegian citizens are happier than American citizens. Is there reason to question the​ results? Select all that apply.

​​-Yes, there is reason. It is not clear how the variable of interest is defined. -​​Yes, there is reason. It is not clear how the variable of interest is measured.

Give examples of several forms of bias. Select all that apply.

-A​​ non-representative sample -An experiment that is not blinded -A researcher with a personal stake in the outcome distorts the true meaning of data

Select each of the following that describes a label that should be included in graphs and the importance of including it.

-If multiple data sets are displayed on a singleIf ​ graph, there should be a legend or key to identify the individual data sets.​ Otherwise, comparisons among the data sets would not be possible and confusion among the data sets could occur. -The graph should have a title or caption ​ (or both) that explains what is being shown​ and, if​ applicable, lists the source of the data. Without this​ label, it might not be clear what the graph is supposed to illustrate. -Numbers along the vertical axis should clearly indicate the​ scale, and there should be a label that describes the variable shown on the vertical axis. Without either of​ these, there would be no way of interpreting the data shown in the graph. -The categories should be clearly indicated along the horizontal​ axis, and there should be a label that describes the variable that the categories represent. Without either of​ these, it would not be possible to know what data the graph is supposed to show.

What two types of graphs are most common when the categories are qualitative​ data? Describe the construction of each. Select the two choices below that correctly answer the question above.

-In a pieIn ​ chart, each category corresponds to a wedge of a circle. The size of each wedge is proportional to the relative frequency of the category it represents. - In a bar ​ graph, the categories are clearly indicated along the horizontal axis. Over each category is a rectangle whose height indicates the frequency or relative frequency of the category. Numbers along the vertical axis clearly indicate the scale.

Identify the sample statistic. Choose the correct answer below.

5 out of 10

Determine how to apply the fourth basic step in a statistical study in this situation. Choose the correct answer below.

The researcher should use the sample statistic as an estimate for the population value of the average number of Th college professors that use presentation software for lectures and then use the methods of statistics to determine how good that estimate is.

What is the distinction between qualitative data and quantitative​ data? Give a few examples of each.

Qualitative data describeQu ​ categories, while quantitative data represent counts or measures. Brand names of shoes in a consumer survey and eye colors are examples of qualitative data. Heights of students and quiz scores are examples of quantitative data.

Identify the population parameter in the given study. Choose the correct answer below.

The percentage of all men in the country who believe there has been progress

Determine how to apply the first basic step in a statistical study in this situation. Choose the correct answer below.

The population is all Th colleges. The researcher wants to estimate the average number of college professors per college that use presentation software for lectures.

Determine how to apply the second basic step in a statistical study in this situation. Choose the correct answer below.

The researcher should gather data about presentation habits from the largest sample of college professors about whom the researcher can gather data.

Determine how to apply the fifth basic step in a statistical study in this situation. Choose the correct answer below.

The researcher should use the methods of statistics to determine the quality of the estimate of the population parameter and draw conclusions based on this estimate accordingly.

Determine how to apply the third basic step in a statistical study in this situation. Choose the correct answer below.

The sample statistic of interest is the average number of college professors per college that nothing use presentation software for lectures.

Consider the following statement about a correlation. State the correlation clearly​ (for example, there is a positive correlation between variable A and variable​ B). Then state whether the correlation is most likely due to​ coincidence, a common underlying​ cause, or a direct cause. Explain your answer. In a large resort​ city, the crime rate increased as the number of taxi cabs increased. There is a positive correlation between the crime rate and the number of taxi cabs. Determine the possible explanation for the correlation. Choose the correct answer below.

This correlation is due to a common underlying cause because it is possibleTh ​ that, with an increase in​ tourism, both the crime rate and the number of cabs increase.