STT Exam 1

Here is the​ five-number summary for the distribution of a cigarette tax​ (in cents) for all the states in a certain country. Minimum=8​ Q1=34​ Median=51​ Q3=102​ Maximum=162 a. About what proportion of the states have cigarette taxes (i) greater than 34 cents and ​(ii) greater than 102 ​cents?

(ii) About 75​% of the states have cigarette taxes greater than 34 cents. (ii) About 25​% of the states have cigarette taxes greater than 102 cents.

Parts of a box and whisker plot. lower whisker: upper whisker: lower edge of box: middle line in box: upper end of the box:

lower whisker: minimum upper whisker: maximum lower edge of box: Q1 (median of first half of data) middle line in box: Q2 (median of the entire data set) upper end of the box: Q3 (median of second half of data)

A company decides to investigate the amount of sick leave taken by its employees. A sample of seven employees yields the following numbers of days of sick leave taken in the past year. 0 1 3 0 0 7 3 b. Find and interpret the standard deviation s.

s=2.58

b. Why is the IQR sometimes preferred to the standard​ deviation? A. The IQR only uses a quarter of the​ data, while the standard deviation uses all the data. B. The IQR uses all the data except the​ outliers, while the standard deviation uses all the data. C. The IQR only includes the largest and smallest​ observations, so it is easier to calculate. D. The IQR is not affected by an​ outlier, while the standard deviation is affected by an outlier.

D. The IQR is not affected by an​ outlier, while the standard deviation is affected by an outlier.

What is the relevance of the​ IQR? A. The IQR summarizes the range for the upper half of the data. B. The IQR summarizes the range for the lower half of the data. C. The IQR summarizes the range within one standard deviation of the mean. D. The IQR summarizes the range for the middle half of the data

D. The IQR summarizes the range for the middle half of the data.

A recent national census found that the median household income in a certain country was $78,100 and the mean was $67,100. Based on only this​ information, what would you predict about the shape of the​ distribution? Why? A. The fact that the mean is less than the median indicates that there are extremely high incomes that are affecting the ​mean, but not the median, suggesting that the shape is skewed to the right. B. The fact that the mean is less than the median indicates that there are extremely low ​incomes, suggesting that the shape is skewed to the right. C. The fact that the mean is less than the median indicates that there are extremely high incomes that are affecting the​ mean, suggesting that the shape is symmetric. D. The fact that the mean is less than the median indicates that there are extremely low incomes that are affecting the ​mean, but not the median, suggesting that the shape is skewed to the left

D. The fact that the mean is less than the median indicates that there are extremely low incomes that are affecting the ​mean, but not the median, suggesting that the shape is skewed to the left

c. What do these data sets illustrate about the resistance of the median and the​ mean? A. The mean is resistant while the median is not. B. Neither the median nor the mean is resistant. C. Both the median and the mean are resistant. D. The median is resistant while the mean is not.

D. The median is resistant while the mean is not.

A company decides to investigate the amount of sick leave taken by its employees. A sample of seven employees yields the following numbers of days of sick leave taken in the past year. Choose the correct interpretation of the range below. A. The range represents the average distance of an observation from the mean. B. The range gives the most useful value for measuring the spread of the data. C. The largest difference between the mean and any other value is equal to the range. D. The number of days separating the fewest and most sick days taken is equal to the range.

D. The number of days separating the fewest and most sick days taken is equal to the range.

a. Why is the standard deviation usually preferred over the​ range? A. The standard deviation is sometimes​ negative, while the range never is. B. The range only uses the largest and smallest​ observations, while the standard deviation uses all the data except the outliers. C. The range is an​ average, while the standard deviation is the actual value. D. The range is more affected by an​ outlier, and the standard deviation uses all the data.

D. The range is more affected by an​ outlier, and the standard deviation uses all the data.

Consider the population of all students at your school. A certain proportion supports increasing the driving age. Your friend randomly samples 15 students from the​ school and uses the sample proportion who support increasing the driving age to predict the population proportion at the school. You take your​ own, separate random sample of 15 students, and find the sample proportion that supports increasing the driving age. (a) For the two​ studies, are the populations the​ same? A. ​No, because the people we choose are not the same. B. No, because we know different people. C. Yes, because the sample sizes are the same. D. Yes, because each sample is randomly chosen from all students in the school.

D. Yes, because each sample is randomly chosen from all students in the school.

What does it look like when a graph is left-skewed?

Longer tail to the left. A slow increase into a peak and then a drop. Larger values in a left-skewed graph.

What does it look like when a graph is right-skewed?

Longer tail to the right. A large increase in the begging and a slow long decrease to the right. There are lots of smaller values with a right-skewed graph.

A travel magazine recently presented data on the annual number of vacation days averaged by residents of eight different countries. They reported 43 days for​ Italy, 38 for​ France, 35 for​ Germany, 33 for​ Brazil, 29 for​ Britain, 26 for​ Canada, 25 for​ Japan, and 14 for the United States. a. Report the median.

Median is 31 days.

A travel magazine recently presented data on the annual number of vacation days averaged by residents of eight different countries. They reported 43 days for​ Italy, 38 for​ France, 35 for​ Germany, 33 for​ Brazil, 29 for​ Britain, 26 for​ Canada, 25 for​ Japan, and 14 for the United States. b. By finding the median of the four values below the​ median, report the first quartile.

Median of the first quartile is 25.5 days.

Values that appear most frequently are known as the...?

Mode

How do you determine IQR?

Q3-Q1

there is no association if the data is...?

Similar

b. What is the definition of modal category?

The category that is the most frequent (category with the largest amount).

Here is the​ five-number summary for the distribution of a cigarette tax​ (in cents) for all the states in a certain country. Minimum=8​ Q1=34​ Median=51​ Q3=102​ Maximum=162 c. Find and interpret the interquartile range.

The interquartile range​ (IQR) is 68.

Here is the​ five-number summary for the distribution of a cigarette tax​ (in cents) for all the states in a certain country. Minimum=8​ Q1=34​ Median=51​ Q3=102​ Maximum=162 b. Between what two values are the middle​ 50% of the observations​ found? The lower bound of the middle​ 50% is...and the upper bound of the middle​ 50% is...

The lower bound of the middle​ 50% is 34 and the upper bound of the middle​ 50% is 102.

On a right-skewed graph is median or mean bigger?

The mean is higher than the median because the graph is right-skewed.

A travel magazine recently presented data on the annual number of vacation days averaged by residents of eight different countries. They reported 43 days for​ Italy, 38 for​ France, 35 for​ Germany, 33 for​ Brazil, 29 for​ Britain, 26 for​ Canada, 25 for​ Japan, and 14 for the United States. c. Find the third quartile.

The median for the third quartile is 36.5 days.

On a left-skewed graph is median or mean bigger?

The median is greater than the mean because the graph is skewed left.

Minimum vs maximum

The minimum of a data set is the lowest value within the data​ set, whereas the maximum of a data set is the highest value within the data set.

A company decides to investigate the amount of sick leave taken by its employees. A sample of seven employees yields the following numbers of days of sick leave taken in the past year. 0 1 3 0 0 7 3 c. Suppose the 7 was incorrectly recorded and is supposed to be 70. What is the new range and st. deviation?

The new range is 70. s=26.05

What is the comparison between a stem-leaf plot and a split stem-leaf plot?

The plot with split stems gives a clearer picture of the shape of the distribution, whereas the regular stem plot shows frequency.

A company decides to investigate the amount of sick leave taken by its employees. A sample of seven employees yields the following numbers of days of sick leave taken in the past year. 0 1 3 0 0 7 3 a. Find and interpret the range.

The range is 7 days.

Sample (STT)

The subset of the population for which we have data.

Population (STT)

The total set of subjects in which we are interested in.

How do you know if a box plot is right or left skewed?

Two of the Q values will be close to each other either to the left or the right. If the values are closer on the right side its right-skewed, and if closer to the left then its left-skewed.

What is the difference between unimodal and bimodal?

Unimodal means there is only one peak on the graph, and bimodal means there are two peaks.

b. Give an example of a categorical variable. Select all that apply. A. Height B. GPA C. Gender D. Religious affiliation

C. Gender D. Religious affiliation

What is a pareto chart?

A bar chart that is ordered based on frequency.

Statistic

A numerical summary of a sample. (smaller portion of the population). Ex) 35,541 people were tested, of which 3,575 tested positive. 3,575/35,541 = 0.100% (10%) is a statistic.

Parameter (STT)

A numerical summary of the population (often unknown). AKA the whole. Ex) The positive rate of COVID-19 of the state of NC.

c. Give an example of a quantitative variable. Select all that apply. A. Age B. Number of siblings C. Sex D. Education level

A. Age B. Number of siblings

On a class​ survey, students were asked to estimate the number of times a​ week, on​ average, that they read a daily newspaper. a. Is this variable continuous or​ discrete? A. Discrete, because the value for each person would be a whole number. B. Continuous, because the newspapers come every day. C. ​Discrete, because the newspapers come every day. D. ​Continuous, because the student was asked for the average.

A. Discrete, because the value for each person would be a whole number.

Consider the population of all students at your school. A certain proportion supports increasing the driving age. Your friend randomly samples 15 students from the​ school and uses the sample proportion who support increasing the driving age to predict the population proportion at the school. You take your​ own, separate random sample of 15 students, and find the sample proportion that supports increasing the driving age. (b) How likely is it that the samples are the​ same? Explain. A. It is very unlikely because the sample is much smaller than the population. B. It is likely because the samples come from the same population. C. It is impossible because the samples come from different populations. D. It is likely because the sample sizes are the same.

A. It is very unlikely because the sample is much smaller than the population.

a. Is the​ variable, number of children​, categorical or​ quantitative? A. The number of children is a quantitative variable. Its values are numerical. B. The number of children is a categorical variable. Its values are numerical. C. The Number of children is a categorical variable. Its values are not numerical. D. The number of children is a quantitative variable. Its values are not numerical.

A. Number of children is a quantitative variable. Its values are numerical.

d. Based on the​ summary, do you think this distribution was​ bell-shaped? If​ so, why? If​ not, why​ not, and what shape would you​ expect? A. The distribution is skewed right because the median is closer to Q1. Further proof is given by the values of the minimum and maximum relative to Q1 and​ Q3, respectively. B. The distribution is skewed left because the median is closer to Q3. Further proof is given by the values of the minimum and maximum relative to Q1 and​ Q3, respectively. C. The distribution is bell-shaped because the median is exactly between Q1 and Q3. Further proof is given by the values of the minimum and maximum relative to Q1 and​ Q3, respectively.

A. The distribution is skewed right because the median is closer to Q1. Further proof is given by the values of the minimum and maximum relative to Q1 and​ Q3, respectively.

A government agency uses a few new sports cars of each model every year to collect data on pollution emission and gasoline mileage performance. For model A​, identify what is meant by​ (a) subject,​ (b) sample, and​ (c) population. (b) What is the sample used by the government​ agency? A. The few new model A sports cars that were chosen for the study. B. All new model A sports cars. C. Sportscars D. Model A sports cars

A. The few new model A sports cars that were chosen for the study.

A government agency uses a few new sports cars of each model every year to collect data on pollution emission and gasoline mileage performance. For model A​, identify what is meant by​ (a) subject,​ (b) sample, and​ (c) population. (a) What is the subject of the study conducted by the government​ agency? A. The new model A sports cars B. The model A sports cars C. Sportscars D. New sports cars

A. The new model A sports cars

One year a survey asked a group of people from a certain country the following​ question, "How many good friends do you have ?"Of the 849 people who​ responded, 9​% reported having only 1 good friend. (b) What is the population for this​ survey? A. The population is the public in the particular country. B. The population is all of the people in the world. C. The population is the 849 people who responded. D. The population is the 9​% who reported having only 1 good friend.

A. The population is the public in the particular country.

One year a survey asked a group of people from a certain country the following​ question, "How many good friends do you have ?"Of the 849 people who​ responded, 9​% reported having only 1 good friend. (a) What is the sample for this​ survey? A. The sample is the people in the particular country who did not respond. B. The sample is the 849 people who responded. C. The sample is the public in the particular country. D. The sample is the 9​% who reported having only one good friend.

B. The sample is the 849 people who responded.

A poll of about 1250 people between the ages of 18 and 34 asked,​ "How concerned are you about the problem of global warming​?" The possible responses were very​ concerned, somewhat​ concerned, not very​ concerned, and​ haven't heard about it. The poll reported percentages (46, 30, 22, 3) in these categories. (a) Identify the sample and the population. Choose the correct answer below. A. The sample is the set of 1250 people that were​ polled, while the population is the set of all people between the ages of 18 and 34. B. The sample is the set of people between the ages of 18 and 34​, while the population is the set of all people. C. The sample is the set of 1250 people that were​ polled, while the population is the set of all people. D. The sample is the set of all people between the ages of 18 and 34 who are concerned about global warming​, while the population is the set of all people between the ages of 18 and 34.

A. The sample is the set of 1250 people that were​ polled, while the population is the set of all people between the ages of 18 and 34.

Choose the correct interpretation of the standard deviation below. A. The standard deviation represents a typical distance of an observation from the mean. B. Since the standard deviation uses the square of the units of measurement for the original​ data, it is not easy to interpret. C. The standard deviation represents finding the deviation for each​ observation, squaring each​ deviation, and then adding them up. D. The standard deviation represents the sum of the deviations from the mean.

A. The standard deviation represents a typical distance of an observation from the mean.

c. What is an advantage of the standard deviation over the​ IQR? A. The standard deviation takes into account the values of all​ observations, while the IQR only uses some of the data. B. The IQR is more difficult to​ determine, while the standard deviation can be found easily. C. The standard deviation uses all the​ data, while the IQR uses all the data except outliers. D. The IQR is an​ average, while the standard deviation is the actual value.

A. The standard deviation takes into account the values of all​ observations, while the IQR only uses some of the data.

One year a survey asked a group of people from a certain country the following​ question, "How many good friends do you have ?"Of the 849 people who​ responded, 9​% reported having only 1 good friend. (c) What is the statistic reported for this​ survey? A. The statistic reported is the percentage of respondents who reported having only 1 good friend (9%). B. The statistic reported is the number of people who responded 849. C. The statistic reported is the number of good friends. D. The statistic reported is the percentage of respondents who reported having more than 1 good friend.

A. The statistic reported is the percentage of respondents who reported having only 1 good friend (9%).

The job placement center at your school surveys all graduating seniors at the school. Their report about the survey provides numerical summaries such as the average starting salary and the percentage of students earning more than ​$40,000 a year. (a) Are the statistical analyses descriptive or inferential​ statistics? A. ​Descriptive, because they summarize the data collected. B. ​Descriptive, because they make predictions about the population. C. Inferential, because they make predictions about the population. D. ​Inferential, because they summarize the data collected.

A. ​Descriptive, because they summarize the data collected.

For 212 alligators captured in four different​ lakes, researchers classified the primary food choice​ (in volume) found in the​ alligator's stomach in one of the categories​ - fish,​ invertebrate, reptile,​ bird, or other. a. Is primary food choice categorical or​ quantitative? A. Quantitative B. Categorical

B. Categorical

a. Is the variable categorical or​ quantitative? Why? A. Number of children in a family is a quantitative variable. Its values are not numerical. B. Number of children in a family is a quantitative variable. Its values are numerical. C. Number of children in a family is a categorical variable. Its values are not numerical. D. Number of children in a family is a categorical variable. Its values are numerical.

B. Number of children in a family is a quantitative variable. Its values are numerical.

b. Is the​ variable, number of children​, discrete or​ continuous? A. Number of children is a continuous variable since it has an infinite continuum of possible values. B. Number of children is a discrete variable since it has a finite number of possible values. C. Number of children is a continuous variable since it has a finite number of possible values. D. Number of children is a discrete variable since it has an infinite continuum of possible values.

B. Number of children is a discrete variable since it has a finite number of possible values.

b. Is the variable categorical or​ quantitative? Why? A. Profession is a quantitative variable. Its values are not numerical. B. Profession is a categorical variable. Its values are not numerical. C. Profession is a quantitative variable. Its values are numerical. D. Profession is a categorical variable. Its values are numerical.

B. Profession is a categorical variable. Its values are not numerical.

One variable in a study measures how many serious motor vehicle accidents a subject has had in the past year. Explain why the mean would likely be more useful than the median for summarizing the responses of the 60 subjects. A. The median uses the numerical values of all the observations. B. Since so many people would report 0 motor​ accidents, the median is not very useful. C. The sample size is small. D. The median is more accurate than the mean.

B. Since so many people would report 0 motor​ accidents, the median is not very useful.

For an exam given to a​ class, the​ students' scores ranged from 36 to 92​, with a mean of 76. Which of the following is the most realistic value for the standard​ deviation: −6, 0, 73, 10, 3? Clearly explain​ what's unrealistic about each of the other values. Choose the correct answer below. A. The most realistic value is −6​ because over half of the data is less than the mean value and the values of 73 and 10 are both implausibly large. B. The most realistic value is 10​ because the negative value is​ impossible, 0 would indicate no​ variability, 3 is too small and 73 is too large for a typical deviation. C. The most realistic value is 73​ because all the other values are too small to fit the given data. D. The most realistic value is 0​, because the negative value is​ impossible, and the values of 3​, 73, and 10 are all too large for a typical deviation.

B. The most realistic value is 10​, because the negative value is​ impossible, 0 would indicate no​ variability, 3 is too small and 73 is too large for a typical deviation.

b. Give an example of each type. Choose the correct answer below. A. The number of copies of a video game sold is a discrete​ variable, while the number of cows on a farm is a continuous variable. B. The number of children in a family is a discrete​ variable, while the time it takes to run a marathon is a continuous variable. C. The distance between two cities is a discrete​ variable, while the number of pets in a household is a continuous variable. D. The weight of an animal is a discrete​ variable, while the height of a giraffe is a continuous variable.

B. The number of children in a family is a discrete​ variable, while the time it takes to run a marathon is a continuous variable.

A survey​ asked, "On the average​ day, about how many hours do you personally watch​ television?" Of 1987​ responses, the mode was 3​, the median was 3​, the mean was 3.83​, and the standard deviation was 3.68. Based on these​ statistics, what would you surmise about the shape of the​ distribution? Why? Choose the correct answer below. A.This distribution is probably​ bell-shaped because the number of responses is large and the distributions of large data sets always have a bell shape. B. This distribution is probably skewed to the right because the mean is larger than the​ median, and the standard deviation is almost as large as the mean. C. This distribution is probably skewed to the left because the mean is smaller than the​ median, and the standard deviation is almost as large as the mean.

B. This distribution is probably skewed to the right because the mean is larger than the​ median, and the standard deviation is almost as large as the mean.

Which of these values are used in the box​ plot? A. mean B. minimum C. median D. maximum E. Q3 F. standard deviation G. Q1

B. minimum C. median D. maximum E. Q3 G. Q1

For the following pairs of​ variables, which more naturally is the response variable and which is the explanatory​ variable? a. Happiness (not too happy, pretty happy, very happy) and Marital status. A. Marital status is the response variable because it is the outcome variable on which comparisons are made and Happiness is the explanatory variable. B. Marital status is the response variable because it defines the groups to be compared with respect to values of Happiness​, the explanatory variable. C. Happiness is the response variable because it is the outcome variable on which comparisons are made and Marital status is the explanatory variable. D. Happiness is the response variable because it defines the groups to be compared with respect to values of Marital status​, the explanatory variable.

C. Happiness is the response variable because it is the outcome variable on which comparisons are made and Marital status is the explanatory variable.

A poll of about 1250 people between the ages of 18 and 34 asked,​ "How concerned are you about the problem of global warming​?" The possible responses were very​ concerned, somewhat​ concerned, not very​ concerned, and​ haven't heard about it. The poll reported percentages (46, 30, 22, 3) in these categories. (b) Are the percentages quoted statistics or​ parameters? Why? A. The percentages quoted are parameters because they are a numerical summary of the entire population. B. The percentages quoted are parameters because they can be used to make decisions or predictions about a population. C. The percentages quoted are statistics because they are a numerical summary of a sample taken from a population. D. The percentages quoted are statistics because they represent all of the possible responses to the poll question.

C. The percentages quoted are statistics because they are a numerical summary of a sample taken from a population.

For the following pairs of​ variables, which more naturally is the response variable and which is the explanatory​ variable? b. Sales and advertising A. Advertising is the response variable because it defines the groups to be compared with respect to values of Sales​, the explanatory variable. B. Advertising is the response variable because it is the outcome variable on which comparisons are made and Sales is the explanatory variable. C. Sales is the response variable because it defines the groups to be compared with respect to values of Advertising​, the explanatory variable. D. Sales is the response variable because it is the outcome variable on which comparisons are made and Advertising is the explanatory variable.

D. Sales is the response variable because it is the outcome variable on which comparisons are made and Advertising is the explanatory variable.

a. Explain the difference between a discrete variable and a continuous variable. Choose the correct answer below. A. A discrete variable has observed values that are clustered in certain​ intervals, while a continuous variable has observed values that are evenly distributed throughout the distribution. B. A discrete variable has infinitely many possible​ values, while a continuous variable is usually a count. C. A discrete variable has each observation belong to one of a set of distinct​ categories, while a continuous variable has observations that take numerical values that represent different magnitudes of the variable. D. A discrete variable has possible values that are separate​ numbers, while a continuous variable has possible values that form an interval.

D. A discrete variable has possible values that are separate​ numbers, while a continuous variable has possible values that form an interval.

a. What is the difference between categorical and quantitative​ variables? A. A categorical variable is any characteristic observed in a study. A quantitative variable is the numerical value associated with each characteristic. B. A variable is called categorical if each observation belongs to one of a set of categories. A variable is called quantitative if observations on it can be placed into one singular categorical group. C. A variable is called categorical if each observation is measured numerically. A variable is called quantitative if observations on it represent different magnitudes of the variable. D. A variable is called categorical if each observation belongs to one of a set of categories. A variable is called quantitative if observations on it take numerical values that represent different magnitudes of the variable.

D. A variable is called categorical if each observation belongs to one of a set of categories. A variable is called quantitative if observations on it take numerical values that represent different magnitudes of the variable.

A government agency uses a few new sports cars of each model every year to collect data on pollution emission and gasoline mileage performance. For model A​, identify what is meant by​ (a) subject,​ (b) sample, and​ (c) population. (c) What is the population for the​ government? A. The few new model A sports cars that were chosen for the study. B. All new motor vehicles. C. All new sports cars. D. All new model A sports cars

D. All new model A sports cars

A company decides to investigate the amount of sick leave taken by its employees. A sample of seven employees yields the following numbers of days of sick leave taken in the past year. 0 1 3 0 0 7 3 c. Suppose the 7 was incorrectly recorded and is supposed to be 70. What is the effect of the​ outlier? A. Both the range and standard deviation decrease when an outlier is added. B. Range increases and standard deviation decreases when an outlier is added. C. Range decreases and standard deviation increases when an outlier is added. D. Both the range and standard deviation increase when an outlier is added.

D. Both the range and standard deviation increase when an outlier is added.

Consider the population of all students at your school. A certain proportion supports increasing the driving age. Your friend randomly samples 15 students from the​ school and uses the sample proportion who support increasing the driving age to predict the population proportion at the school. You take your​ own, separate random sample of 15 students, and find the sample proportion that supports increasing the driving age. (c) How likely is it that the sample proportions are the​ same? Explain. A. It is likely that the sample proportions will be the same because the sample represents the same population. B. It is very unlikely that the sample proportions will be the same because the samples come from different populations. C. It is likely that the sample proportions will be the same because the sample sizes are the same. D. It is unlikely that the sample proportions will be exactly the same.​ However, they should be close to each other because the samples represent the same population.

D. It is unlikely that the sample proportions will be exactly the same.​ However, they should be close to each other because the samples represent the same population.

For the following pairs of​ variables, which more naturally is the response variable and which is the explanatory​ variable? c. Number of children and mothers age A. Mother's age is the response variable because it defines the groups to be compared with respect to values of number of children​, the explanatory variable. B. Number of children is the response variable because it defines the groups to be compared with respect to values of Mother's age​, the explanatory variable. C. Mother's age is the response variable because it is the outcome variable on which comparisons are made and number of children is the explanatory variable. D. Number of children is the response variable because it is the outcome variable on which comparisons are made and Mother's age is the explanatory variable.

D. Number of children is the response variable because it is the outcome variable on which comparisons are made and Mother's age is the explanatory variable.

c. Is the variable categorical or​ quantitative? Why? A. Number of sick days taken in a year is a categorical variable. Its values are not numerical. B. Number of sick days taken in a year is a quantitative variable. Its values are not numerical. C. Number of sick days taken in a year is a categorical variable. Its values are numerical. D. Number of sick days taken in a year is a quantitative variable. Its values are numerical.

D. Number of sick days taken in a year is a quantitative variable. Its values are numerical.

The job placement center at your school surveys all graduating seniors at the school. Their report about the survey provides numerical summaries such as the average starting salary and the percentage of students earning more than ​$40,000 a year. (b) Are these numerical summaries better characterized as statistics or as​ parameters? A. Statistics​, because the analyses summarize data on a sample B. Statistics, because the analyses summarize data on a population. C. Parameters, because the analyses summarize data on a sample. D. Parameters​, because the analyses summarize data on a population.

D. Parameters​, because the analyses summarize data on a population.

d. Is the variable categorical or​ quantitative? Why? A. Political party preference is a quantitative variable. Its values are not numerical. B. Political party preference is a quantitative variable. Its values are numerical. C. Political party preference is a categorical variable. Its values are numerical. D. Political party preference is a categorical variable. Its values are not numerical.

D. Political party preference is a categorical variable. Its values are not numerical.

What does it mean to truncate data?

Drop the last number (if there are three digits) and add a zero.

When using a split stem-leaf plot what set of numbers goes into the first stem of 1 and the second stem of 2 and so on.

First stem of a number always goes 0-4. Second stem gets 5-9.

How do you determine an outlier?

If an value is less that Q1-1.5 IQR or bigger than Q3+1.5 IQR than its considered an outlier.

Can you have more than one sample in the same population?

Yes

Is it common to get different statistics from the different samples within the population?

Yes

a. Find the median for each data set. Set​ 1: 9​, 10​, 11​, 12​, 13 Set​ 2: 9​, 10​, 11​, 12​, 100 Set​ 3: 9​, 10​, 11​, 12​, 1000

a. The median of set 1 is 11 The median of set 2 is 11 The median of set 3 is 11

b. Find the mean for each data set. Set​ 1: 9​, 10​, 11​, 12​, 13 Set​ 2: 9​, 10​, 11​, 12​, 100 Set​ 3: 9​, 10​, 11​, 12​, 1000

b. The mean of set 1 is 11 The mean of set 2 is 28.4 The mean of set 3 is 208.4