PY 211 EXAM 1 HW QUESTIONS

What is the midpoint of a distribution when n=34?

17.5

Calculate the population variance for the following set of data: 52, 43, 55, 53, 49, 46 Give your answer accurate to two decimal places.

17.22

An instructor measures a student's homeowork grades: 70, 70, 74, 79, 83, 85, 88, 89, 92, 97. Calculate the range and enter your answer below.

27

Calculate the sample variance for the following set of data: 40, 40, 58, 50, 43, 46 Give your answer accurate to two decimal places.

48.17

The median is appropriate for which variables? a. A grading scale with the values Poor, Fair, Good, Excellent b. All the options c. Admissions test score (e.g., ACT, SAT, GRE) d. Last degree obtained (high school, associate's, bachelor's, master's, doctoral)

b. All the options

Which of these variables is continuous? a. Primary school grade level b. Angle of the sun above the horizon c. Voting age in the United States d. Military rank

b. Angle of the sun above the horizon

For which variable could the mean be calculated? a. All of the options b. Response time (in seconds) c. Favorite sport d. Native language e. Perceived difficulty of an exam (easy, moderate, challenging)

b. Response time (in seconds)

Identify an example of variability. a. Total number of births in 2018 was 3,791,712. b. Exam 1 scores ranged from 65% to 99%. c. The most common eye color is brown. d. The average height of adult males in the United States is 69.3 inches.

b. Exam 1 scores ranged from 65% to 99%.

When is it most likely that the median > mean? a. Positively-skewed distribution b. Negatively-skewed distribution c. Symmetric distribution

b. Negatively-skewed distribution

In what way does a histogram differ from a bar graph? a. A histogram can be used with ratio-level variables on the x-axis. b. Frequency is represented by bar height in a bar graph. c. The y-axis on a histogram typically starts with 0. d. A histogram displays frequency on the y-axis.

a. A histogram can be used with ratio-level variables on the x-axis.

Your instructor told you the class exam mean and exam standard deviation as she was passing back the exam. The standard deviation was 1.5. Interpret this value. a. A typical exam score was 1.5 points from the mean. b. The arithmetic mean of the deviation scores was 1.5. c. The range of exam scores was 1.5 points on either side of the mean. d. The lowest exam score was 1.5 points below the mean.

a. A typical exam score was 1.5 points from the mean.

Which shows how many observations there are for each value of a variable? a. Distribution b. Rolling average c. Percent d. Differential

a. Distribution

Which measure of central tendency should be reported for the variable state of residence? a. Mode b. Range c. Mean d. Median

a. Mode

Identify an example of variability. a. The difference among final exam scores for 55 students b. The average life span of adults in the United States c. The median home price in Florida d. The median home price in Florida and the average life span of adults in the United States

a. The difference among final exam scores for 55 students

Knowing that the number of days per year during which a person uses alcohol or drugs is positively skewed, which of the following are true? a. The mean number of days is greater than the modal number of days. b. The mean number of days equals the median number of days. c. The modal number of days is a larger value than the median number of days. d. The median number of days is a smaller value than the modal number of days.

a. The mean number of days is greater than the modal number of days.

Select the accurate difference between the population variance calculation and the sample variance calculation. a. The sample variance has a denominator of n − 1. b. The population variance does not include deviation scores. c. The sample variance has a denominator of N. d. The population variance has a numerator of SS − M.

a. The sample variance has a denominator of n − 1.

On a computer display, Senju and Hasegawa (2005) showed participants a face that either gazed at or away from the participant. Participants were asked to stare at the face, but to quickly detect the same target when it appeared at different positions around the periphery of the screen. Participants were slower in detecting the appearance of the target when the face looked at the participants. Which of these was a constant for this study? a. Type of target b. Gaze alignment c. Response speed d. Target location

a. Type of target

The order of the bars in a bar graph for a nominal-level variable is a. arbitrary. b. determined by frequency of occurrence. c. from highest to lowest. d. from lowest to highest.

a. arbitrary.

As a whole, a histogram depicts the _____ of the variable of interest. a. distribution b. frequency of occurrence c. the nominal to ordinal ratio d. the nominal to ordinal interval

a. distribution

Graphed data for a distribution with a small standard deviation will have a _____ compared to graphed data for a distribution with a larger standard deviation. a. higher peak in the middle b. larger range c. lower peak in the middle d. smaller mean

a. higher peak in the middle

The mode is the ______ value in a distribution. a. most frequent b. middle c. 1st d. nth

a. most frequent

You might choose to use quantitative, statistical methods because you believe them to be more a. objective AND easily summarized. b. objective. c. easily summarized. d. comprehensive.

a. objective AND easily summarized.

Researchers compared the attractiveness ratings of men photographed with different hair lengths, classified as short hair, medium hair, and long hair. This measurement of hair length would be considered a. ordinal level. b. interval level. c. ratio level. d. nominal level.

a. ordinal level.

If you were interested in measuring how clustered data were around the mean, then the most helpful measure of variability is a. standard deviation. b. variance. c. mean. d. range.

a. standard deviation.

Which series of values could have come from the x-axis of a histogram? a. 15; 40; 50; 65; 85; 95; 110; 120; 125; 140 b. 10; 20; 30; 40; 50; 60; 70; 80; 90; 100 c. red; orange; yellow; green; blue; indigo; violet d. private; corporal; sergeant; lieutenant; captain; major; colonel; general

b. 10; 20; 30; 40; 50; 60; 70; 80; 90; 100

If the standard deviation of a sample of test scores is 8, then the variance is a. 16. b. 64. c. 2.83. d. indeterminate.

b. 64.

A researcher calculated a mean of 8.52 hours of sleep per night and a variance of 1.88 for a sample of 20 undergraduates. Which of the following is the correct interpretation of the variance? a. The scores were all within 1.88 hours of the mean. b. The average squared deviation from the mean is 1.88. c. A typical score deviated from the mean by 1.88 hours. d. Most of the scores were within 1.88 hours of the mean.

b. The average squared deviation from the mean is 1.88.

Stull et. al. (2018) divided a large lecture into a group that used a model to follow along with the instructor's demonstration of a chemistry topic and a group that only watched the instructor use a model to learn about the same chemistry topic. Student understanding was measured on a later exam. Which of these was a constant for this study? a. Students' understanding b. The chemistry topic c. Students' gender d. Instructional method

b. The chemistry topic

The mean value for a set of 15 values is 4.3. A new value of 5 is added to the data set. What will happen to the mean value? a. The mean will change to 5. b. The mean will increase. c. The mean will stay the same. d. The mean will decrease.

b. The mean will increase.

The APA Publication Manual (American Psychological Association, 2020) indicates that a. research summaries must always include a graph. b. graphs should follow specific formatting guidelines. c. graphs are overused in research publications. d. the formatting of graphs may vary for each research journal.

b. graphs should follow specific formatting guidelines.

Variability can be observed a. very rarely in scientific research. b. in most aspects of everyday life. c. only in the quantitative variables. d. in measures of central tendency.

b. in most aspects of everyday life.

Relating the number of times a few of your friends post to Twitter to the number of times a typical user posts to Twitter is an example of using _____ statistics. a. descriptive. b. inferential. c. qualitative. d. biased.

b. inferential.

Chaplin et. al. (2020) found differences in happiness among children aged 3 to 17 when they received gifts of material goods versus experiences. The scale of measurement for type of present, measured as either material goods or experiences, would be a. ratio. b. nominal. c. interval. d. ordinal.

b. nominal.

Why might it be important to identify the minimum and maximum age values for a study on social media use by teenagers? a. The average age of the teenagers would be important for reporting the findings. b. These values are necessary to identify the modal age for the study. c. 12 to 14 year olds may use social media differently than 15 to 17 year olds. d. The deviation of a typical age score from the average age would be useful.

c. 12 to 14 year olds may use social media differently than 15 to 17 year olds.

Mandarin speakers describe time as vertical. Boroditsky (2001) noted that Mandarin speakers were faster to confirm that March comes before April if they were primed with a visual array of objects when the same objects were aligned vertically rather than aligned horizontally. Which of these was varied by the researchers for this study? a. Performance measure b. Type of objects to compare c. Alignment of objects d. Language

c. Alignment of objects

Which of these variables is categorical? a. Temperature in degrees Celsius b. Shoe size c. Blood type d. Age in years

c. Blood type

Which of the following is needed to determine the "look" of a set of data? a. Variability b. Central tendency c. Central tendency and variability d. None of these

c. Central tendency and variability

Select the variable that would be appropriate for a frequency distribution displayed in a histogram. a. Place of finish in eight-runner races (first, second, and so on) b. Pizza size (small, medium, or large) c. Commute to work (in minutes) d. Favorite ice cream topping (chocolate, strawberry, marshmallow cream)

c. Commute to work (in minutes)

Beege et. al. (2017) investigated whether the facing direction of the instructor influenced students' learning performance and social rapport. Which of these was varied by the researchers for this study? a. Learning performance of the student b. Social rapport between student and instructor c. Facing direction of the instructor d. Instructor presence

c. Facing direction of the instructor

Which of the following accurately describes the use of graphs? a. Graphs are most useful to summarize one variable at a time. b. Graphs break up the flow of the text to improve readability. c. Graphs can provide an efficient way to summarize data. d. Graphs should always replace verbal descriptions of numeric data.

c. Graphs can provide an efficient way to summarize data.

Which of these variables is discrete? a. Completion time b. Car model c. Population total d. Marital status

c. Population total

To investigate the role of hand gestures in communications, Cook et. al. (2008) manipulated whether children were required to use hand gestures while speaking or speak without hand gestures on a mathematical learning task. Which type of variable were hand gestures in this study? a. Discrete b. Continuous c. Qualitative d. Quantitative

c. Qualitative

Kelly et. al. (2005) investigated the development of face recognition by measuring the looking time of newborns and 3-month-old infants to faces that either matched the ethnicity of their parents or did not. What was the scale of measurement for the variable looking time, measured in seconds, for this study? a. Nominal b. Ordinal c. Ratio d. Interval

c. Ratio

Which variable(s) would be appropriate to use on the x-axis of a frequency polygon? a. Native language b. Food preference or native language c. Reaction time d. Food preference.

c. Reaction time

In Class A, the mean exam score was 80 with a standard deviation of 10. In Class B, the mean exam score was 80, but the standard deviation was 5. Which of these is true of Classes A and B? a. The sum of squares in Class A was smaller than the sum of squares in Class B. b. There is more variability in Class B. c. The average distance between individual scores and the mean is smaller in Class B. d. The students in Class B performed better than the students in Class A.

c. The average distance between individual scores and the mean is smaller in Class B.

Exam scores in a difficult math course have a bimodal distribution with a peak at the A range and a peak at the C range. Which measure of central tendency would be appropriate to report and why? a. The median would be appropriate because it would be most helpful to know the value between the two peaks. b. The mean would be appropriate because exam score is a ratio variable. c. The mode would be appropriate because both of the peaks (modes) would be reported and are useful to describe the typical responses of participants. d. For a distribution with more than one peak, central tendency is not a useful measure.

c. The mode would be appropriate because both of the peaks (modes) would be reported and are useful to describe the typical responses of participants.

Why is the range an important measure in addition to the minimum and maximum values? a. The range provides information on the average deviation from the mean. b. The range provides information about the center of a distribution. c. The range conveys information about the spread of a variable. d. The range tells you if the distribution is skewed.

c. The range conveys information about the spread of a variable.

One variable included in the General Social Survey is the highest education level of the respondent's mother. Select an example of variability for this variable. Yes, that's correct! a. The most frequent education level reported b. The median education level reported c. The range of education levels reported d. None of the choices are examples of variability

c. The range of education levels reported

Which of the following is accurate? a. The variance is the square root of the standard deviation. b. The standard deviation is the arithmetic mean of the deviations from the sample mean. c. The standard deviation is measured on the same scale as the original observations. d. The standard deviation equals the average squared deviation score.

c. The standard deviation is measured on the same scale as the original observations.

A researcher collected two samples of salivary cortisol levels (in micrograms per deciliter) from young adult women. In Sample A, with sample size of 15, the sample variance was .082. In Sample B, with sample size of 40, the sample variance was .077. Which of the following statements is true? a. The sample mean must have been positive in Sample A and Sample B. b. The variability of the samples cannot be compared because the sample sizes were different. c. There was more variability in Sample A. d. There was more variability in Sample B.

c. There was more variability in Sample A.

In which of the following situations would a graph be most useful? a. To display the results of a simple data set that included one variable with two categories. b. To provide a visual depiction of each participant's response to a 52 question survey. c. To convince readers to follow health advice by displaying a drug's efficacy compared to a control group who consumed a placebo. d. To distract readers from contradictory data.

c. To convince readers to follow health advice by displaying a drug's efficacy compared to a control group who consumed a placebo.

A sample consists of observations from a. all members of a population. b. one member of a population. c. any subset of a population. d. half of a population.

c. any subset of a population.

Calculating the average number of times a few of your friends post to Twitter is an example of using _____ statistics. a. inferential b. both inferential and descriptive c. descriptive d. neither inferential nor descriptive

c. descriptive

Income is a well-known example of a positively-skewed distribution. With the amount of income increasing from left to right on the x-axis as normal, the most extreme values in such a distribution will be found a. to the left side of the graph. b. to both the left and right sides of the graph. c. to the right side of the graph.

c. to the right side of the graph.

n a study of reading times, if the sample mean is 54 seconds and the variance is 11, then the standard deviation is a. 54 ± 11. b. 121. c. 22. d. 3.32.

d. 3.32.

Which of these variables is a quantitative variable? a. Political affiliation b. Eye color c. Marital status d. Breathing rate

d. Breathing rate

Guilmoto (2015) used Indonesia's 2010 census to measure the proportion of male to female children across the archipelago. A proportion of 1.0 represents an equal number of both sexes, less than 1.0 represents fewer males than females, and greater than 1.0 represents more males than females. Which type of variable was the proportion of male to female children in this study? a. Categorical b. Qualitative c. Discrete d. Continuous

d. Continuous

For which variable would a histogram be appropriate? a. Eye color b. College major c. College rank d. Hours of sleep the previous night

d. Hours of sleep the previous night

Which of the following variables could be used to create a histogram? a. Hometown b. T-shirt size c. College major d. Nights socializing per week

d. Nights socializing per week

One way to measure sharing behavior in preschoolers would be to count the number of times a child chose to share a new toy that was recently introduced. The number of sharing behaviors would be considered which level of measurement? a. Interval b. Nominal c. Ordinal d. Ratio

d. Ratio

Why might a graph be unnecessary to summarize the following data?Out of the 20 survey participants, 10 preferred studying with background noise and 10 preferred studying in silence. a. Survey results should not be summarized with graphs. b. Readers do not need to be persuaded to study in silence. c. The data includes a nominal-level variable. d. The data can be easily and clearly summarized with a verbal description.

d. The data can be easily and clearly summarized with a verbal description.

Which of the following are equal to the mode? a. Winner of the 100 meter sprint in the Olympics b. None of the options c. The midpoint of a skewed distribution d. The most popular item selected from a vending machine

d. The most popular item selected from a vending machine

A researcher plans to measure the relationship between percent of homework assignments completed and final exam grade (in points). Can she report the same measure of central tendency for both variables? a. No, one variable is ratio and one variable is interval. b. Yes, you should always report the same measure of central tendency. c. No, you should always report different measures of central tendency. d. Yes, both variables are ratio.

d. Yes, both variables are ratio.

The y-axis on a scatterplot is a. frequency of occurrence. b. a nominal variable. c. relative frequency of occurrence. d. any interval- or ratio-level variable.

d. any interval- or ratio-level variable.

It is commonly assumed that a normal body temperature is 98.6 degrees Fahrenheit. Obermeyer et. al. (2017) questioned this assumption in a longitudinal study in which they collected temperature measurements from 38,488 healthy participants. The scale of measurement for temperature in degrees Fahrenheit is a. ordinal. b. nominal. c. ratio. d. interval.

d. interval.

The best form of central tendency for home prices in a large city, such as Los Angeles, where there are likely to be some million dollar homes, along with most homes priced much lower, would be the a. mode. b. mean. c. variance. d. median.

d. median.

If you were interested in measuring the breadth of the data, then the most helpful measure of variability in graphed data is a. mean. b. variance. c. standard deviation. d. range.

d. range.

A sample _____ is used to estimate a population _____. a. qualitative observation; quantitative observation b. parameter; statistic c. parameter; data set d. statistic; parameter

d. statistic; parameter

In a study of simple reaction time to the onset of a buzzer in which 100 observations have been collected, the addition of a new observation is most likely to have the biggest effect on a. none of the options because it will affect them equally. b. the mode. c. the median. d. the mean.

d. the mean.

Typically the x-axis of a bar graph shows a. percent. b. the distribution. c. frequency. d. the values of the variable of interest

d. the values of the variable of interest

Finding the median includes a step requiring calculation of a mean when a. the data set is skewed. b. there is an odd number of values in the data set. c. the data set is not skewed. d. there is an even number of values in the data set.

d. there is an even number of values in the data set.

The mode is the only measure of central tendency that is appropriate for the ____ level(s) of measurement. a. nominal and ordinal b. interval c. ordinal d. ratio e. nominal f. interval and ratio

e. nominal