Public Health Statistics: Chapter 1

The entire collection of information that is going to be analyzed is called ___

A) Material

B) A data set

C) Datum

D) A cluster

B) A data set

The approach to mathematics where data is organized, summarized, and interpreted is called ___.

A) Algebra

B) Chemistry

C) Geometry

D) Statistics

D) Statistics

What is the primary computational software used for statistical analyses?

A) SPSS

B) R-Prime

C) MATLAB

D) ANOVA

A) SPSS

The beginning of ___ statistics can be said to have started when scientists first began collecting information from a population.

A) Understandable

B) Computational

C) Descriptive

D) Inferential

C) Descriptive

The mean, median, and mode are all measures of ___.

A) Common data

B) Differentiation

C) Central tendency

D) Specific scores

C) Central tendency

Measures of central tendency give information about ___.

A) The distribution of scores

B) The dependability of scores

C) The reliability of scores

D) The validity of a single score

A) The distribution of scores

One of the first ways in which data is summarized is by computing a(n) ___.

A) Norm

B) Center

C) Average

D) Standard

C) Average

Miguel teaches statistics at the local high school. He finds that most of his students scored close to an 85 on the final exam. Eighty-five most closely represents the class ___.

A) Grade

B) Group

C) Total

D) Average

D) Average

You are computing measures of central tendency from a data set. You end up with n = 60, x-bar = 75.13, s² = 15.15, and a range of 47 - 93. What is the mean?

75.13

A researcher computes the mean for a group of scores and ends up with this number: 12.14579. Statisticians typically will shorten this number to ___.

A) 12.14

B) 12.146

C) 12.15

D) 12.1458

C) 12.15

Which statement correctly describes how to compute the mean?

A) The sum of all the scores, divided by the number of scores

B) The number of scores, divided by the sum of all the scores

C) The number of scores, multiplied by the sum of all the scores

D) The sum of all the scores, multiplied by the number of scores

A) The sum of all the scores, divided by the number of scores

The symbol X in statistics refers to ___.

A) A group of means

B) A single mean

C) A group of scores

D) A single score

D) A single score

The ___ is the score in which 50% of scores fall above that score and 50% fall below that score.

A) Mode

B) Median

C) Mean

D) Macro

B) Median

An extremely high or low score is called a(n) ___

A) Exception

B) Outlier

C) Irregularity

D) Deviation

B) Outlier

Researchers use the term ___ when a distribution is significantly distorted due to having outliers present.

A) Bias

B) Slant

C) Curve

D) Skew

D) Skew

Kenya has measured the height of the starting five basketball players at a local high school. Their heights are 5’11, 6’0, 5’9, 6’3, and 7’2. Which measure of central tendency would be the best to use if she wanted to describe the average height of the team?

A) Variance

B) Mode

C) Median

D) Mean

C) Median

The subset of a population that researchers select to participate in a study is called the ___.

A) Sample

B) Prototype

C) Test

D) Selected

A) Sample

The mode is a measure of the average that relies on ___.

A) Difference data

B) Mean data

C) Complex data

D) Frequency data

D) Frequency data

The entire group of people that a researcher is interested in studying is called the ___.

A) Sample

B) Collection

C) Subjects

D) Population

D) Population

A department store wants to know which men’s shirt size sells the most so they can be sure to order enough when restocking. The shirt sizes they carry are small, medium, large, X-large, and XX-large. Which measure should be used to determine which size they sell most of?

A) Mean

B) Mode

C) Median

D) Common

B) Mode

What measure of central tendency do most people mean when they say “average”?

A) Median

B) Ratio

C) Mode

D) Mean

D) Mean

A teacher would most likely use ___ to summarize how their class did on a quiz.

A) Descriptive statistics

B) Differential equations

C) Inferential statistics

D) Score variability

A) Descriptive statistics

To estimate the attitude of a population of people, you should use ___.

A) Score variability

B) The median

C) Inferential statistics

D) Descriptive statistics

C) Inferential statistics

Which of the following is the largest?

A) A population

B) A distribution of scores

C) A sample

D) A mean

A) A population

Why do we call averages measures of central tendency?

A) They describe trends over time

B) They are in the middle of a distribution

C) They are the most important descriptive statistic

D) They identify the most representative value.

D) They identify the most representative value

Which of the following is an example of descriptive statistics?

A) Testing whether a new drug is more effective than an old one

B) Determining if there is a relationship between two variables

C) Predicting future population growth based on past trends

D) Calculating the average test score of a class

D) Calculating the average test score of a class

Why do scientists use measures of central tendency like the mean, median, and mode?

A) To summarize large amounts of data in a meaningful way

B) To manipulate data and get the results they want

C) To determine the statistical significance of an experiment

D) To establish cause-and-effect relationships

A) To summarize large amounts of data in a meaningful way

If a teacher wants to calculate the mean test score for a class, what steps should they take?

A) Arrange all the test scores in order and find the middle number

B) Add up all the test scores and divide by the number of students

C) Subtract the lowest score from the highest score

D) Identify the most common score that appears in the data set

B) Add up all the test scores and divide by the number of students

True or False: It is easier to calculate the mean of a sample than the mean of a population

True

In inferential statistics, what is always being used to infer to a population?

A) The highest score

B) The lowest score

C) A sample

D) A measure of central tendency

C) A sample

A data set consists of the following numbers: 4, 7, 9, 10, 12. What is the median of this data set?

9

A data set contains the values 3, 5, 7, 7, 10, 12, 12, 12, 15. What is the mode?

12

What are descriptive statistics and why are they useful? Provide an example.

Descriptive statistics are set of computational tools that are used to describe and summarize data sets. Descriptive statistics are necessary for when a researcher wants to understand a group of people. We use descriptive statistics when we want to know about the average score or performance of a sample. For example, a professor may want to know how a class performed on an exam. Instead of looking at each individual score the professor may compute a measure of central tendency such as the mean, median, or mode. In other words, descriptive statistics can tell us how a group of people performed overall.

Compare and contrast the three measures of central tendency.

The three measures of central tendency are the mean, median, and mode. These three measures are similar in that each are designed to describe an aspect of the average for a group of scores in a data set. The mean is most commonly used measure of central tendency and describes the average of a data set by summing the individual scores and dividing that number by the total number of scores. Unlike the median and mode, the mean is affected by extreme scores. The median is second measure of central tendency and refers to the middle of a distribution. The median is score is one in which 50% of the scores lie above it and 50% of the scores lie below it. Although the median isn’t as meaningful as the mean in terms of describing a data set, it is useful when outliers are present because it is not affected by scores that are extremely high or low. The mode is the least precise measure of central tendency. The mode refers to the most frequent score that occurs. Although it may be less meaningful then either mean or median, there are circumstances in which you might have to use it. For example, the mode is the only measure of central tendency that can be used for data that is measured on at the nominal level.

Why is mean the most common measure of central tendency and under what circumstances would it best to use a different measure of central tendency?

The mean at the most basic level is the mathematical average. It is the most common measure of central tendency because statisticians typically work with numerical values. It is very useful for describing averages. However, there are some cases in which the mean is not always the best or most useful measure of central tendency. For example, you cannot compute the mean if you are using variables that are categories or non-numerical such as room color, or academic major. In these cases the mean wouldn’t be very meaningful. Also, the mean is sensitive to very high or low scores. The extreme values are called outliers can influence the mean in such a way that it provides misleading information about a set of data or people.

Explain what the median is and when it is most useful?

The median is another measure of central tendency that refers to the middle score. It is a description of the average but it does the information it conveys is typically not as meaningful as the mean. To find the median you simply count up the number of scores and find the value that splits the data in half. Or if the data you are working with contains an even number of scores you add the two middle scores up and divide by two. The median simply splits the data set in half right down the middle. The median is useful when outliers skew the data to either the high or low side. Descriptive statistics is about gathering information about the average. Thus, in those cases the median may be the better measure of central tendency for describing the set of data.

Explain what the mode is and when you would use it. Provide an example.

The mode is the most imprecise measure of central tendency, however, there are times when the mode is the only measure of central tendency that can be used. The mode is simple to compute because all it refers to is the score or value that occurs most, or is the most frequent, in a set of data. The mode is used when researchers are investigating variables that are not numerical. For example, the mode is the only measure you can use for variables that are at the nominal level. For example, a researcher my be looking at eye color, or the type of vehicles. These are categorical variables that use names not numbers. Thus, measures such as the mean and median wouldn’t be very useful or meaningful. However, with the mode we can talk.

Suppose you are finding the median for the following set of values: 10, 13, 7, 8, 15, 10, 19, 5, and 3. What is the first step in the process?

A) Find the mid-point

B) Count the values

C) Determine the range

D) Order the values

D) Order the values

The most common measure of central tendency is the ___.

A) Standard deviation

B) Mode

C) Median

D) Mean

D) Mean

Which symbol denotes the mean for a group of scores?

A) Beta

B) X-bar

C) Capital Sigma

B) X-bar

Historically speaking, the field of statistics started when people began to attach numbers to ___.

A) People

B) Symbols

C) Outcomes

D) Symptoms

C) Outcomes

According to you text, knowledge of statistics allows us to make decisions based on ___ evidence.

A) Inferential

B) Subjective

C) Empirical

D) Descriptive

C) Empirical

Suppose a teacher is examining student test scores. The distribution of scores are as follows: 63, 76, 71, 76, 83, and 92. The score 71 is the mid-point of the distribution and is known as the ___.

A) Mean

B) Mode

C) Median

D) Standard deviation

C) Median

What would you be computing if using this equation:

A) Mean

B) Median

C) Variance

D) Mode

A) Mean

According to the text, small n is used to represent samples and capital N is used to represent ___.

A) Sample

B) Populations

C) Score

D) Mean

B) Populations

Before taking a statistics course, students often find statistics ___.

A) Intimidating

B) Unrealistic

C) Exciting

D) Easy

A) Intimidating

Inferential statistics are used to answer questions about a ___.

A) Population

B) Person

C) Sample

D) Data set

A) Population

In statistics, what does this symbol mean?

A) Sum all the scores

B) Divide all the scores

C) Multiply all the scores

D) Multiply one score

A) Sum all the scores

A data set has the following values: 4, 25, 30, 23, 31, 26, 36, 32, 28, and 92. In this case why is the median more useful than the mean?

A) Because we want to avoid using scores that have decimals

B) Because outliers affect the mean but not the median

C) Because it is easier to use the median than the mean

D) Because there are an even number of scores

B) Because outliers affect the mean but not the median

Katrina is working with a small set of numerical data. She is doing a lot of her descriptive statistic calculations by hand. She adds up all the scores and then divides that number by the total number of scores in the data set. What best describes the value Katrina is computing?

A) A single value that shows the skew of the distribution

B) A single value that illustrates the range of scores

C) A single value that describes the variance of the data

D) A single value that represents the average score

D) A single value that represents the average score

Suppose you are conducting research. What is the first thing you need to do with your data?

A) Interpret it

B) Organize it

C) Classify it

D) Summarize it

B) Organize it

Jeneice is collecting data on the average starting income for drug counselors. She has 115 participants. 75 of her participants are men and 40 are women and they have an average age of 25. Starting incomes range from $32,000 to $70,000 per year. The mean starting salary is $45,500 per year. According to Jeneice’s data, what is the mode?

A) The mode is the lowest income range of $32,000 per year

B) The mode cannot be determined

C) The mode is the number of male participants

D) The mode is the mean salary of $45,000 per year

B) The mode cannot be determined

Which of the following are the 3 measures of central tendency?

A) Percentile, quartile, z-score

B) Standard deviation, variance, alpha

C) Mean, median, mode

D) Square root, average, range

C) Mean, median, mode

Suppose a researcher is collecting IQ data. All of the IQ scores that are collected fall between 75 and 115. However, there is one score of 150. How would this extreme score affect the mean?

A) It would make the mean IQ higher than it really is

B) It would have no effect on the mean IQ

C) It would make the mean IQ lower than it really is

D) It would affect the median score not the mean score

A) It would make the mean IQ higher than it really is

Which statement provides a description of what statistics are?

A) The disciplines that require complex mathematical computations

B) The different ways in which a researcher can recruit participants

C) The techniques used to organize, summarize, and interpret data

D) The methods used to collect data from a population of people

C) The techniques used to organize, summarize, and interpret data

McKenna is a graduate student at a large university. She wants to know what the average height is for females at her school. The university that McKenna attends has 23,000 females. What should McKenna do when it comes to collecting her data?

A) McKenna should obtain all the phone numbers of the female students and call each one

B) McKenna should collect data from a subset, or sample, of the female students population

C) McKenna should email every female student asking about their height and wait for the replies.

B) McKenna should collect data from a subset, or sample, of the female students population

In order to trust the result of analysis you must ___.

A) Have lots of data

B) Know advanced statistics

C) Use statistical software for analyses

D) Trust your data

D) Trust your data

A researcher wants to know the average salary for middle school teachers in the state of California. Middle school teachers in California represent the ___.

A) Mode

B) Data

C) Population

D) Sample

C) Population

The median is also known as the ___.

A) 75th percentile

B) 95th percentile

C) 25th percentile

D) 50th percentile

D) 50th percentile

Kasan wants to know if there are certain personality types that are more common in people who are pursuing degrees in the social sciences. He gives a personality test to a large group of people and records his findings. Kasan is collecting ___.

A) Information

B) Personalities

C) Figures

D) Data

D) Data

Kaleb is looking at which science majors are the most popular at his university. The department of science has four majors: biology, chemistry, psychology, and mathematics. Which measure of central tendency should Kaleb use for describing the distribution of majors?

A) Mean

B) Mode

C) Average

D) Median

B) Mode