Questions and Answers of Introduction To Statistical Investigations

Reconsider Exercise 3.3.24 about the average number of states all students at the author’s school have visited. Recall that in the author’s sample of 136 students the average number of tates the
In a July 2018 Gallup poll that surveyed 1,033 randomly selected U.S. adults, 5% said that they considered themselves vegetarians. a. Describe what the parameter is in this context. b. The
Suppose a 95% confidence interval for a population proportion is (0.27, 0.49). Rewrite this interval in the form of p? ± margin of error.
Which confidence interval would be the narrowest? A. 99% B. 95% C. 90% D. 85%.In order to investigate how many hours a day students at their school tend to spend on course work
The General Social Survey (GSS), conducted every other year, uses a random sample of U.S. adults to gather data on contemporary American society. One of the questions in the 2018 GSS was, “A doctor
Student researchers wanted to determine a person’s ability to estimate the number of beans in a bag. They had 1,470 beans in a clear bag for the subjects to estimate. They also showed the subjects
Do people think they look different than they actually do? In particular, do they think they look better? Researchers Epley and Whitchurch (2008) tried to answer this question by taking pictures of
With the increased use of credit cards, debit cards, and other electronic methods of payment, will the United States eventually stop using cash? In a July 2016 Gallup poll of a random sample of 1,024
The General Social Survey (GSS) uses a random sample of U.S. adults to answer a variety of questions. From the 2018 survey, one question asked was, “On the average day, about how many hours do you
The General Social Survey (GSS) uses a random sample of U.S. adults to answer a variety of questions. From the 2018 survey, one question asked was the age of the respondent when their first child was
Student researchers wanted to know whether students at their school could accurately estimate the length of a 17-second song snippet on average. They played 17 seconds of Corinne Bailey Rae’s song
A Gallup poll from January 2018 found that only 39% of adult Americans planned on watching a great deal/fair amount of the Winter Olympic Games. This information can be used to estimate the
Suppose we are constructing a confidence interval using repeated tests of significance to develop an interval of plausible values. Using two-sided tests each time with the following null hypothesized
Suppose we are constructing a confidence interval using repeated tests of significance to develop an interval of plausible values. Using two-sided tests each time with the following null
Which confidence interval would be the narrowest? A. 99% B. 95% C. 90% D. 85%In order to understand why consumers visit their store, a local business conducts a survey by asking
Based on a June 2019 Gallup poll, a 95% confidence interval for the proportion of American adults that are in favor of free tuition at a community college for anyone who wants to attend is 0.61 to
An eighth-grade student in Canada was concerned that air dryers in public restrooms were too loud, especially when measured at the height of children’s ears. Her results were eventually published
Reconsider Exercises 3.3.24 and 3.3.25 about the average number of states all students at the author’s school have visited. Recall that in the author’s sample of 136 students the average number
In a June 2019 Reuters poll based on a representative sample of 400 American independent voters, 65% responded they support samesex marriages. Now suppose we test the null hypothesis π = 0.50 vs.
Recall Questions 4.1.1 and 4.1.2 about intrinsic motivation and position in the classroom. Which of these is the response variable? A. The classrooms B. The health science students C.
Recall Question 4.1.1 about intrinsic motivation and position in the classroom. Which of these is the explanatory variable? A. The classrooms B. The health science students C. The
A study done in France (Uffler et al., 2017) explored whether there is an association between a student’s intrinsic motivation and where they sit in class. More specifically, they studied 593
A study done in the Netherlands (Stulp et al., 2015) looked to see whether a person’s height is related to their status. To test this they found a narrow passage at the entrance of a supermarket
A 2019 Ipsos poll of 4,000 U.S. adults found that 65% play video games on their computer, gaming console, or smartphone. a. Use this sample result and a theory-based approach to produce three
Refer to Exercise 3.4.32 to answer (a) and (b): a. If the sample size had been 8,000, how would the widths of the 90%, 95%, and 99% confidence intervals be affected? b. If the sample size
A 2015 Gallop poll of 15,747 U.S. adults who had a smartphone found that 72% checked their phones about once every hour. Based on these data we found the 95% confidence interval for the proportion of
Show that the margin-of-error formula simplifies to approximately 1/√n when p? = 0.5 1.96√p(1-P)/n
A 2018 General Social Survey (GSS) asked a random sample of 1,118 adult Americans how often they contacted their closest friend by either phone, internet, other communication device, or face to face.
Although flipping a coin should result in 50% heads in the long run, what proportion of the time will spinning coins on a table result in landing heads up? Determine this with a coin of your choice,
Founded in 1890, the Literary Digest was a popular magazine in the early 1900s. The magazine correctly predicted the outcomes of the 1916, 1920, 1924, 1928, and 1932 presidential elections by
A group of 11 students were asked how many texts they sent yesterday. Put the results, which are in the file Texts, into the One Mean applet and create a bootstrap sampling distribution. Based on the
What do you expect the means and standard deviations of the distribution of sample proportions to be for these population parameters and sample sizes? a. π = 0.25, n = 40 b. π = 0.25, n =
Scores on a recent statistics exam had a mean of 82.7 and a median of 87. If your score on this exam was an 84, did more students in the class have scores higher than yours or lower than yours?
In the Sampling Words applet with the Gettysburg Address using the variable short, the horizontal axis of the population represents whether or not a word is short—a categorical variable. When you
For each of the statements (a)–(d), indicate whether it is true or false. a. The distribution of the variable height can be skewed to the right. b. The distribution of the variable
One of the key ideas in Section 2.1 is that the standard deviation of a distribution of sample proportions is estimated bywhen the population large enough, where large enough was when the population
In the Sampling Words applet with the Gettysburg Address using the variable length, the numbers on the horizontal axis of the graph for the population distribution represent the length of the
For each of the statements (a)–(d), indicate whether it is true or false. a. The distribution of the variable sex can be skewed to the left. b. The distribution of the variable age can be
Recall Exercise 2.CE.13 about healthy human body temperatures. Suppose you are testing the following hypotheses: H0: μ = 98.6°F, Ha: μ ≠ 98.6°F. You recruit 30 healthy subjects and find their
State the appropriate null and alternative hypotheses to be tested. Of the 1,858 cell phone users, 13% admitted to faking cell phone calls in the past 30 days.A reporter for International Business
A report from Pew Research Center in 2015 found that in a sample of 929 cell phone users ages 13 to 17, the respondents sent and received an average of 67 texts per day while the median number of
Suppose you are testing to see whether human body temperatures tend to be lower than 98.6°F (what is thought to be the average body temperature) with the following hypotheses: H0: μ = 98.6°F, Ha:
According to the National Health Service (NHS), which provides healthcare for all UK citizens based on their need for healthcare rather than their ability to pay for it, the normal weight of a
Based on your answer to Exercise 2.4.12, what sort of conclusion can you make and how are you determining this? A. We have strong evidence that the difference in ages for husbands and wives is
Suppose you are testing to see whether bags of potato chips have an average weight that is larger than their label weight of 10 oz with the following hypotheses: H0: μ = 10 oz, Ha: μ > 10 oz.
A t-distribution looks a lot like a normal distribution, but it is a bit more spread out than a normal distribution with more observations in the “tails,” fewer in the middle. To determine
When assigning symbols to statistics and parameters, which of A–H is correct? (Choose all that are correct.) A. p is the sample proportion, π is the population proportion. B. x is the
Shift the sample data appropriately and find a p-value. A. 0.0001 B. 0.0491 C. 0.2518 D. 0.5014
Go to the Sampling Words applet and load some penny data by clicking the Pennies radio button located just to the right of the data window. This dataset contains the last two digits of the year on
The Gettysburg Address has 268 words and the average word length is 4.29 letters. If we are going to randomly choose words from that speech, which of A–C is least likely to happen? A. Randomly
Use the One Mean applet to take at least 10,000 samples from the MarriageAgesDiff data to develop a bootstrap sampling distribution for the mean. Which of A–D is the closest to the standard
Do you feel comfortable generalizing your conclusions to all cell phone users? If not, is there a population you feel you can generalize your conclusions to? Now suppose you asked 1,858 people
Use the One Mean applet, choose the Bootstrapping option at the top, and paste in the MarriageAgesDiff data. What are the mean and standard deviation for the data (with the appropriate
Which of A–D is FALSE? A. We use the symbol μ to represent the population mean. B. We use the symbol x to represent the sample mean. C. The symbols p and x are both used to
What are the appropriate null and alternative hypotheses for this study? A. H0: x = 0 years; Ha: x > 0 years B. H0: μ = 0 years; Ha: μ > 0 years C. H0: π = 0 years; Ha: π
Suppose instead of just asking the respondents whether they have ever faked a phone call, the interviewer said, “Research has shown that only 5% of adult Americans with cell phones have faked a
The administration at a local high school is considering building a new gym. In order to find out how the student body feels about this, a student organization decides to conduct a survey of the
When developing a bootstrap sampling distribution for a mean, we shift the sample data so it is centered on: A. 0. B. 0.50. C. The mean of the sample. D. The value of the mean in
Suppose instead of just asking the respondents whether they have ever faked a phone call, the interviewer said, “Many college students use apps that help them creatively fake a phone call. Have you
Was the sample random? Was the sampling method unbiased?Have you ever pretended to be talking on your cell phone in order to avoid interacting with people around you? Is faking cell phone calls a
The administration at a local high school is considering building a new gym. In order to find out how the student body feels about this, a student organization decides to conduct a survey of the
Suppose the distribution of the length of the words in this chapter has a mean of 5 words and a standard deviation 2.7 words. Also suppose I take repeated samples of 10 words from all the words in
According to a 2018 report by the U.S. Department of Labor, civilian Americans spend 2.84 hours per day watching television. A faculty researcher, Dr. Sameer, at California Polytechnic State
What is the primary reason why we create a bootstrap sampling distribution? A. To see where the distribution is centered B. To see what shape the distribution will have C. To see how
When developing a bootstrap sampling distribution, we repeatedly take samples that are: A. Smaller than the original sample size. B. The same size as the original sample. C. Larger
Which of A–D are the correct validity conditions for a one-sample t-test? A. You should have at least 10 success and at least 10 failures in your sample.B. You should have at least 10 success
When developing a bootstrap sampling distribution, we repeatedly take random samples: A. With replacement from the population. B. Without replacement from the population. C. With
The Gettysburg address has 268 words and 41.0% of the words are short (3 or fewer letters). If we are going to randomly choose words from that speech, which of A–C is least likely to
Which of A–D is correct? A. μ and σ represent statistics whereas x and s represent parameters. B. s and σ represent statistics whereas x and μ represent parameters. C. x and s
A convenience sample of 105 statistics students reported the number of texts they sent yesterday, and the results are shown in the Exercise 2.2.4 graph. Which of the A–D statements is true about
Was the sample random? Was the sampling method unbiased?Have you ever pretended to be talking on your cell phone in order to avoid interacting with people around you? Is faking cell phone calls a
Suppose you have a large bucket containing 40% red gummy bears and 60% green gummy bears. You take many, many random samples of 25 gummy bears and each time note the proportion that are red. From
A one-sample t-test gives more valid p-values with: A. Larger sample sizes and sample distributions that are fairly skewed B. Larger sample sizes and sample distributions that are fairly
Suppose you have a large bucket containing 40% red gummy bears and 60% green gummy bears. You take many, many random samples of 25 gummy bears and each time note the proportion that are red. From
Twenty-nine college students were asked how many states in the United States they have been to and the results are shown here. 1, 3, 3, 5, 6, 8, 9, 10, 11, 12, 12, 12, 13, 13, 14, 15, 16, 16,
A t-distribution is shaped like a normal distribution but is: A. A bit skewed in one direction or the other. B. A bit taller in the middle than a normal distribution. C. Not quite as
Suppose instead of just asking the respondents whether they have ever faked a phone call, the interviewer said, “Research has shown that that 80% of adult Americans with cell phones have faked a
In Exploration 2.1, you used an applet to take many samples of words from the Gettysburg Address, found the proportion of short words in each sample, and then created a distribution of the sample
The more left skewed a distribution is: A. The smaller the percentage of data values that are above the mean. B. The larger the percentage of data values that are above the mean. C.
The correct formula for calculating a t-statistic is which of A–D? A. t = (x? − μ0)/s B. t = (x? − μ0)/σ C. t = (x? − μ0)(s/√n?) D. t = (x? − μ0)/(σ/√n?)
The more right skewed a distribution is: A. The smaller the percentage of data values that are below the mean. B. The larger the percentage of data values that are below the mean. C.
Was the sample random? Was the sampling method unbiased?Have you ever pretended to be talking on your cell phone in order to avoid interacting with people around you? Is faking cell phone calls a
We can reduce the possibility of having bias in a study by: A. Increasing the sample size. B. Making sure our sample is a simple random sample. C. Using a one-sided alternative
Suppose you are told that the average wingspan of an American robin is 35 cm and you want to test this out for the robins in your area. You capture 40 robins to use as your sample and find that the
Recall Exercise 1.1.31 about whether chimpanzees are more likely to pick the container containing more bananas rather than the one with fewer bananas. In another set of 20 trials (again with 3
What are the observational units?A legendary story on college campuses concerns two students who miss a chemistry exam because of excessive partying but blame their absence on a flat tire. The
In 2015 there was a viral story about the colors of a dress in a picture. Some saw the colors as blue and black and others saw them as white and gold. Suppose you take a sample of 100 people and ask
Suppose you are conducting a test of significance to try to determine whether your cat, Hope, will go to the correct object (out of two) when it is pointed to, just like Harley the dog did in the
According to the National Coffee Drinking Study from the National Coffee Association, 40% of 18- to 24-year-olds in the United States regularly drink coffee every day. Suppose this number is
In the scenario from Exercise 1.1.3, what are the observational units? A. The 100 trials B. Whether or not Hope goes to the correct object C. The long-term proportion (probability)
In the scenario from Exercise 1.1.3, what is the variable? A. The 100 trials B. Whether or not Hope goes to the correct object C. The long-term proportion (probability) that Hope will
Suppose a friend of yours says she is a 75% free-throw shooter in basketball. You don’t think she is that good and want to test her to gather evidence that she makes less than 75% of her free
The theorem that states that if the sample size is large enough, the distribution of sample proportions will be bell-shaped (approximately normal), centered at the long run proportion π, with a
Reconsider the scenario in Exercise 1.4.4 about coffee consumption. Which of A–E is the appropriate sample statistic and proper symbol? A. p̂ = 0.40 B. π = 0.40 C. p̂ =
In the scenario from Exercise 1.1.3, what is the statistic? A. The 100 trials B. Whether or not Hope goes to the correct object C. The long-term proportion (probability) that Hope will
Reconsider Exercises 1.4.4 and 1.4.5 about coffee consumption. Suppose you use an applet and find a null distribution with mean of 0.400 and standard deviation of 0.041. What is the value of the
Suppose 10 coins are flipped, and the proportion of heads is recorded. This process is repeated many, many times to develop a distribution of these sample proportions. What is the predicted mean and
Suppose you are testing the hypotheses: H0: π = 0.60 and Ha: π > 0.60 and your sample proportion is 0.61. From this you determine that your standardized statistic is 0.53. What is the correct
What is calculated using the formula √(1-π)/n?
Student researchers were interested in whether people will be more likely to choose the name-brand cookie (Chips Ahoy) over the store-brand (Chipsters) in a blind taste test. They tested this with 20

Showing 900 - 1000 of 1041