STATS: CH 1 Final Review

Two researchers, studying the behavior of wolves at Isle Royale National Park in Lake Superior, collect the following information about a pack of five wolves:

· Each wolf’s gender.

· Each wolf’s height (in inches) measured from photographs!

· The average number of hours per day each wolf spends hunting.

· Whether each wolf prefers to hunt in the woods, in fields, or shows no preference.

· An estimate of the average weight (in pounds) of food eaten per day by each wolf.

Which of the following best describes the individuals and variables that are being measured?

• The two researchers are the individuals. There are two categorical variables and three quantitative variables.

• The five wolves are the individuals. There are three categorical variables and two quantitative variables.

• The five wolves are the individuals. There are two categorical variables and three quantitative variables.

• The two researchers are the individuals. There are three categorical variables and two quantitative variables.

A team of twelve researchers at an educational research company asked a random sample of 1000 high school students from across the U.S. about their smart phone use. The team of researchers recorded the following information:

· Each student’s gender.

· How many text messages each student sent in the past week.

· What social media each student uses most often (Instagram, Twitter, Facebook, etc.).

· How much time each student spent on phone calls in the past week.

· What app each student used most often in the past week.

Which of the following best describes the individuals and variables that are being measured?

• The 1000 high school students are the individuals. There are two categorical variables and three quantitative variables.

• The 1000 high school students are the individuals. There are three categorical variables and two quantitative variables.

• The twelve researchers are the individuals. There are three categorical variables and two quantitative variables.

• The twelve researchers are the individuals. There are two categorical variables and three quantitative variables.

A random sample of 6 dogs were selected. The owners helped the dogs demonstrate the number of tricks they were able to perform. The results were 12, 9, 7, 3, 8, and 2 tricks. What is the standard deviation of the number of questions that were answered incorrectly by these students? Interpret this value.

• The standard deviation is about 3.76 tricks. The number of tricks completed typically varies by about 3.76 tricks from the median.

• The standard deviation is about 14.14 tricks. The number of tricks completed typically varies by about 14.14 tricks from the mean.

• The standard deviation is about 14.14 tricks. The number of tricks completed typically varies by about 14.14 tricks from the median.

• The standard deviation is about 3.76 tricks. The number of tricks completed typically varies by about 3.76 tricks from the mean.

Here are parallel dotplots of the total number of medals earned by individual Olympic athletes in swimming and athletics (track and field) who have won multiple Olympic medals. Which of the following are correct?

I. The distributions of total number of medals earned for both swimming and track and field athletes are skewed to the right and single-peaked.

II. The center of distribution of the total number of medals earned by swimmers tends to be greater than the center of the distribution of the total number of medals earned by track and field athletes.

III. The total number of medals earned by swimmers varies more than the total number of medals earned by track and field athletes.

• II and III

• I only

• I and II

• I, II, and III

The histogram displays the fuel economy (in miles per gallon) for a random sample of 1000 vehicles.

Which of the following is correct?

• The histogram is roughly symmetric. Approximately 68% of vehicles achieve between 25 and 35 mpg.

• The histogram is roughly symmetric. Approximately 58% of vehicles achieve between 25 and 35 mpg.

• The histogram is skewed to the right. Approximately 68% of vehicles achieve between 25 and 35 mpg.

• The histogram is skewed to the left. Approximately 58% of vehicles achieve between 25 and 35 mpg.

A statistics teacher was curious about the distribution of cost for his electric bills from the last 12 months. Here are the data.

$82.68 $77.02 $70.01 $54.87 $52.62 $70.88

$86.74 $73.94 $86.61 $59.89 $55.28 $70.93

Which of the following responses contains the correct boxplot and a true statement about the distribution of electric bills?

• 
• 
• 
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Here are summary statistics that describe the distribution of the number of steps taken by a group of teachers on a randomly selected school day as recorded by a Fitbit. What is the z-score for a teacher who took 10,250 steps? Interpret this value.

• z = –0.944. This teacher’s steps for the day were 0.944 standard deviations below the mean of 11,278 steps.

• z = 0.944. This teacher’s steps for the day were 0.944 standard deviations above the mean of 11,278 steps.

• z = –0.944. This teacher’s steps for the day were within 0.944 standard deviations of the mean of 11,278 steps.

• None of these are correct.

Here are summary statistics that describe the distribution of the number of steps taken by a group of teachers on a randomly selected school day as recorded by a Fitbit. What is the z-score for a teacher who took 14,012 steps? Interpret this value.

• z = –0.103. This teacher’s steps for the day were 0.103 standard deviations below the mean of 13,890 steps.

• z = 0.103. This teacher’s steps for the day were 0.103 standard deviations above the mean of 13,890 steps.

• z = 0.103. This teacher’s steps for the day were within 0.103 standard deviations of the mean of 13,890 steps.

• None of these are correct.

Which of the following variables is quantitative?

• age group (0-9, 10-19, 20-29, etc.)

• zip code

• income bracket

• amount of sleep received last night

Which of the following variables is categorical?

• number of pairs of shoes owned

• height

• whether or not a person has a driver’s license

• age (in years)