Question 1

The table shows the weights (in pounds)and monthly incomes (in dollars)of nine randomly selected women between the ages of 18 and 65. $$\begin{array} { r | c | c | c | c | c | c | c | c | c } 
\text { Weight (lb) } & 113 & 132 & 155 & 122 & 166 & 140 & 118 & 129 & 185 \
\hline \begin{array} { r } 
\text { Monthly Income } \
\text { (dollars) }
\end{array} & 1420 & 3650 & 5475 & 2310 & 4710 & 2910 & 1720 & 2460 & 4115
\end{array}$$ If we use statistical methods to conclude that there is a correlation (or relationship or association)between the weights of women and their monthly incomes, can we conclude that by increasing her weight a woman can increase her monthly income?

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The answer of The table shows the weights (in pounds)and...

Question 2

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.

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Question 3

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.

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The answer of Identify the sample and population. Also, determine...

Question 4

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?

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Question 5

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

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Question 6

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.

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Question 7

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

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Question 8

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. $$\begin{array} { r | c c c c c c c c } 
\text { Athlete } & \mathbf { A } & \mathbf { B } & \mathbf { C } & \mathbf { D } & \mathbf { E } & \mathbf { F } & \mathbf { G } & \mathbf { H } \
\hline \text { Before } & 115.2 & 114 & 116.4 & 119.8 & 110.9 & 112.4 & 111.5 & 117.3 \
\hline \text { After } & 112.9 & 112.7 & 114 & 120.6 & 109.1 & 109.1 & 107.9 & 113.4
\end{array}$$ 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?

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The answer of A coach uses a new technique in...

Question 9

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

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Question 10

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.

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Question 11

Would an observational study or an experiment be more appropriate to investigate the effects on fertilizer on plant growth? Explain.

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Question 12

Given the data in the table, what issue can be addressed by conducting a statistical analysis of the values? $$\begin{array}{l}
\text { Amounts of Saturated Fat (in grams) in Two-Once Regular and Low-Fat Muffins }\
\begin{array} { l | l l l l l l } 
\text { Regular } & 4.5 & 3.5 & 3.7 & 5.2 & 4.9 & 3.9 \
\hline \text { Low-Fat } & 1.2 & 2.1 & 2.2 & 1.8 & 1.6 & 2.2
\end{array}
\end{array}$$

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Question 13

Why is cluster sampling frequently used in practice?

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Question 14

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?

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Question 15

Distinguish between categorical and quantitative data. Give an example of each

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Question 16

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

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Question 17

"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?

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The answer of "38% of adults in the United States...

Question 18

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?

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The answer of A lawyer surveyed a simple random sample...

Question 19

Explain the difference between stratified and cluster sampling.

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Question 20

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?

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The answer of A teacher was interested in knowing how...

Quiz 1: Introduction to Statistics

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.

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

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

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

Would an observational study or an experiment be more appropriate to investigate the effects on fertilizer on plant growth? Explain.

Why is cluster sampling frequently used in practice?

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?

Distinguish between categorical and quantitative data. Give an example of each

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

"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 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?

Explain the difference between stratified and cluster sampling.

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?