stats exam chapter 1, Statistics Chapter 4, Statistics Chapter 3, Statistics Chapter 2 Quiz
Which of the following terms are least likely to be used to describe qualitative data? nominal descriptive categorical numeric
numeric
Which graphical display lists percentages and not original scores
ogive
A researcher distributes frequencies into the following intervals: 1-10, 11-20, 21-30, 31-40, 41-50, and 51 and above. What is wrong with this frequency distribution?
one interval is an open class
A percentile is
a percentile point
What is the percentile point at the 50th percentile for the following distribution?
25
The size of a population is symbolized as ________, whereas the size of a sample is symbolized as ________. μ; M M; μ n; N N; n
N; n
A percentile is also called a:
percentile point
Measures of variability can range in value from -∞ to + ∞ 0 to + ∞ It depends on whether the variability is positive or negative. It depends on the value of the mean for a given distribution.
0 to + ∞
researcher records the following scores for an Olympic gymnast following her routine: 9.9, 9.8, 9.6, 9.5, 9.7, 9.1, 8.9, and 9.8. What is the range for the scores? 1.0 (9.9 to 8.9) 0.3 (9.8 to 9.5) 0.5 (9.6 to 9.1) It is not possible to compute a range with an even number of scores.
1.0 (9.9 to 8.9)
The sum of relative frequencies for each interval is _____
1.00
What is the percentile point at the 90th percentile in the following distribution?
10
A researcher decides to split scores on an exam into quartiles. She determines that a score of 64 is at the 25th percentile, a score of 74 is at the 50th percentile, and a score of 80 is at the 75th percentile. What is the interquartile range (IQR) for these data? 16 10 6 There is not enough information to answer this question.
16
A researcher selects a sample of 6 males and 11 females. She asks participants to rate the likelihood they would do female-stereotyped jobs (such as nursing or school teaching) on a scale from 1 = not likely at all to 5 = very likely. Men indicated that they would be less likely to do these jobs (M = 2.1) compared with women (M = 4.3). What is the weighted mean for this entire sample of 17 participants? 2.1 4.3 3.2 3.5
3.5
As a general rule, a simple frequency distribution should have between
5 and 20 intervals
A researcher measures the time (in seconds) it takes a sample of 26 participants to respond to a stimulus presented on a computer screen. The standard deviation for response times is 6. In this example, what is the value for SS? 36 150 900 There is not enough information to answer this question.
900
Fill in the missing values for A and B in this frequency distribution table:
A = 3.2, B = 13
A researcher records the following scores on a working memory quiz for two samples. Which sample has the largest standard deviation? Sample A: 2, 3, 4, 5, 6, 7, and 8 Sample B: 4, 5, 6, 7, 8, 9, and 10 Sample A Sample B Both samples have the same standard deviation.
Both samples have the same standard deviation.
Grouped data are to ungrouped data as
Continuous is to discrete
Which of the following is NOT a characteristic of the mean? Add a score above the mean and the mean will increase. Add a score below the mean and the mean will decrease. Delete a score below the mean and the mean will increase. Delete a score above the mean and the mean will increase.
Delete a score above the mean and the mean will increase.
A researcher distributes frequencies into the following intervals: 3-6, 7-10, 11-15, 16-18, 19-22, and 23-26. What is wrong with this frequency distribution?
The interval width is unequal.
Which of the following is NOT a rule for constructing a simple frequency distribution?
The number of intervals should equal the number of values measured
Researchers rarely have access to entire populations. How do researchers resolve this limitation? They do not need to resolve this; it is not a limitation at all. They record data from an entire population of people to make inferences concerning characteristics in a sample. They record data from as many persons in a population as possible to draw conclusions concerning only those individuals. They record data from a sample of people in the larger population in order to make inferences concerning characteristics in that larger population.
They record date from a sample of people in the larger population in order to make inferences concerning characteristics in that larger population
The mode is an appropriate measure of central tendency for data that are bimodal use with other measures of central tendency data that are on a nominal scale all of the above
all of the above
The range, a measure of variability, is the difference between the largest (L) and smallest (S) value in a list of scores is the most informative when used to describe data sets without outliers includes only two values in its computation, regardless of the number of scores in a distribution all of the above
all of the above
The sample variance is: an unbiased estimator of the population variance associated with n - 1 degrees of freedom computed by dividing SS by df all of the above
all of the above
A population can be ____ group of interest to a researcher. any only one only a small only a large
any
A simple frequency distribution
can be used to summarize grouped data can be used to summarize ungrouped data summarizes the frequency of scores in a given category or range [all of the above]
Ungrouped data can be distributed as
categories
Adding the same constant to each score in a distribution (or subtracting the same constant from it) will cause the mean to change by that constant not change the mean at all because the same constant was added to or subtracted from each score
cause the mean to change by that constant
Multiplying or dividing each score in a distribution by the same constant will cause the mean to change by that constant not change the mean at all because each score was multiplied or divided by the same constant
cause the mean to change by that constant
A health practitioner measures the heart rate (in beats per minute) of patients under low, moderate, and high stress levels. Heart rate can be best described as continuous data discrete data a qualitative variable the independent variable
discrete data
The definitional formula ______ the computational formula for SS. estimates explains diminishes equals
equals
Interval scales of measurement have equidistant scales have a true zero both a and b
have equidistant scales
The advantage of squaring the deviation of each score from the mean and then summing is that it makes the sample variance an unbiased estimator of the population variance it makes the degrees of freedom for sample variance equal to n - 1 it produces a minimal positive solution that is not zero, so long as all scores are not exactly the same value both A and C
it produces a minimal positive solution that is not zero, so long as all scores are not exactly the same value
The distribution of personal income for U.S. citizens is positively skewed. If the median annual income is $44,000, this implies that the mean annual income is smaller larger the same There is not enough information to answer this question.
larger
A researcher records the time (in seconds) that participants arrive late for a scheduled research study. Assuming these data are normally distributed, which measure of central tendency is most appropriate to describe these data? mean median mode range
mean
The ________ is the sum of all scores (in a sample or population) divided by the number of scores summed. mode median mean range
mean
An animal researcher measures the number of times a rat presses a lever located at the right, center, and left of a cage for a food reward. What scale of measurement is the location of lever pressing? nominal ordinal interval ratio
nominal
A researcher compares the amount of college debt (in dollars) that undergraduate students incur up to their four-year degree. College debt is on what scale of measurement? nominal ordinal interval ratio
ratio
To determine the interval width, we divide the ________ by the number of intervals.
real range
Bar charts are a lot like histograms, except
the bars displayed in the graph do not touch
You are interested in measuring the construct, work expertise. Which of the following measures for this construct is quantitative and discrete? the total time in hours spent working at a company the job title a person holds in a company the percent of correct responses on a work expertise survey the number of employees that work under an employee
the number of employees that work under an employee
What is the corresponding percentile of a percentile point
the percentile rank
A percentile point is
the value of a score on a measurement scale below which a specified percentage of scores in a distribution fall
All other things being equal (so assuming that the value of SS never changes), as sample size increases, the degrees of freedom for sample variance decrease the value of sample variance decreases the value in the numerator for sample variance increases the value in the denominator for sample variance decreases
the value of sample variance decreases
Which characteristic of a histogram implies that it summaries continuous data?
the vertical bars touch at the upper boundary of each interval
A relative frequency distribution is appropriate when
there are large frequency counts in each interval
Regardless of the number of scores in a distribution, the range only includes ___ score(s) in its calculation. one two at most two the average
two
A(n) ________ is a sample statistic that equals a population parameter on average. biased estimator degrees of freedom unbiased estimator sum of squares
unbiased estimator
The following frequency distribution is an example of
ungrouped data
A staff member records the number of victories (per 10-game season) for a new football coach during his first three seasons with a team. The coach won 1, 3, and 8 games respectively over the three seasons. Which conclusion is appropriate? The football coach won an average of four games per season. The football coach won a median of three games per season. The football coach won 40% of his games during his first three seasons. All of the above
All of the above
Which of the following values is NOT needed to compute sample variance using the computational formula, but is needed to compute the definitional formula? sample mean scores (x) sample size degrees of freedom
sample mean
Which type of mean is used to describe a portion of individuals in a given population? sample mean population mean restricted mean none of the above
sample mean
Researchers measure data in a ________ to learn more about individuals in the larger _______ of interest. sample; population statistic; inference population; sample inference; statistic
sample population
A characteristic (usually numeric) that describes a sample is called a sample sample statistic population population parameter
sample stat
Which of the following measures of attraction is an example of a ratio scale measurement? a rating of attraction from most attractive to least attractive a 6-point rating scale from 1 (attractive) to 6 (unattractive) the status of the relationship (acquaintance, dating, married) the physical proximity (in feet and inches) between two romantic partners
the physical proximity (in feet and inches) between two romantic partners
You are interested in measuring the construct, reinforcement. Which of the following measures for this construct is quantitative and continuous? the number of rewards received the type of reward (food, money) the size of a reward in grams the rating of a reward on a scale from 1 (not reinforcing) to 7 (very reinforcing)
the size of a reward in grams
A researcher identifies college students as a group of interest to test her hypothesis. She then identifies a few local college students and selects a small group of the local college students to be observed. In this example, the sample is: not clearly identified all college students the few local college students the small group of college students who here observed
the small group of college students who were observed
A student scores in the 80th percentile on an exam. What does this mean in comparison to all other students?
the student scored higher than 80% of all others who took the exam
A researcher computes the computational formula for SS, as finds that ∑x = 39 and ∑x2 = 271. If this is a sample of 6 scores, then what would SS equal using the definitional formula? 17.5 3.5 232 not possible to know because the sample mean is not given
17.5
A researcher finds that 12% of participants make between 3-5 visits to a physician each year. What are the real limits for this interval?
2.5-5.5
A researcher reports that 12 persons in a sample of 60 reported getting between 4 and 6 hours of sleep per night. What is the relative percentage for this interval?
20%
The following is a simple frequency distribution table. If we convert this frequency distribution to relative percentages, which of the following gives the corresponding percentages in each interval listed from the top down.
20%, 13%, 17%, 33%, 17%
A researcher computes the definitional formula for SS, as finds that ∑(x-M)2 = 44. If this is a sample of 12 scores, then what would the value of sample variance be using the computational formula? 3.7 4.0 44
4.0
A researcher computes the computational formula for SS, as finds that ∑x = 22 and ∑x2 = 126. If this is a sample of 4 scores, then what would SS equal using the definitional formula? 4 5 104
5
The following is a simple frequency distribution table. Suppose we convert this table to a cumulative frequency distribution. The frequencies in each interval of the cumulative frequency distribution would be
5, 8, 10, 14, 20 (top down summary) 6, 10, 12, 15, 20 (bottom up summary) [both A and B, depending on how the data were summarized]
A researcher computes the definitional formula for SS, as finds that ∑(x-M)2 = 112. If this is a sample of 20 scores, then what would the value of population variance be using the computational formula? 5.6 5.9 112 not possible to know because the scores are not given
5.6
A researcher records the following scores: 5, 3, 7, 6, 2, 8, 0, and 1. In terms of these data, the sum of the squared differences of scores from their mean is 0 8 32 60
60
A researcher records the time in seconds it takes a sample of participants to walk alone through a dark portion of campus. The researcher computes SS = 1,200. Assuming that a sample of 25 participants was observed in this study, what is the standard deviation for these data? 48 seconds 50 seconds 6.9 seconds 7.1 seconds
7.1 seconds
A psychologist treats 16 patients and records the number of sessions required to complete a behavioral therapy treatment for each patient. She computes SS = 800. Assuming the 16 patients constitute all patients under her care (so the population of her patients), what is the standard deviation for these data? 53.3 sessions 50 sessions 7.1 sessions 7.3 sessions
7.1 sessions
What is the percentile point at the 80th percentile in the following distribution?
8
A researcher records the sound (in decibels) during a series of lessons taught by a substitute teacher at a local elementary school. In his study, he found that the sound was 80±6 (M±SD) decibels. Assuming the data are normally distributed, which of the following is an appropriate conclusion? 68% of classes were between 68 and 80 decibels. 5% of classes were louder than 68 decibels. 95% of classes were between 68 and 92 decibels. all of the above
95% of classes were between 68 and 92 decibels.
A researcher reports that the time (in minutes) it takes children who are "picky eaters" to finish their vegetables is negatively skewed, with children finishing their vegetables in 4.2±1.0 (M±SD) minutes. Based on Chebyshev's theorem, we can conclude that 68% of children finished their vegetables in 3.2 to 5.2 minutes. 50% of children finished their vegetables in at least 3.2 minutes. 99.7% of children finished their vegetables in 2.2 to 6.2 minutes. At least 89% of children finished their vegetables in 1.2 to 7.2 minutes.
At least 89% of children finished their vegetables in 1.2 to 7.2 minutes.
State the type of graphical display for Graph A and Graph B. Refer to the Image.
B is a bar chart; A is a histogram.
The mathematical term ∑x is the numerator for the population mean the sample mean Both A and B None; this term is not in the numerator for any calculation.
Both A and B
A researcher records the following motor assessment scores for two samples of athletes. Which sample has the largest standard deviation? Sample A: 8, 10, 12, 15, and 18 Sample B: 16, 18, 20, 23, and 26 Sample A Sample B Both samples have the same standard deviation.
Both samples have the same standard deviation.
If a portion of people from a population are asked to complete an assessment, then the average score among that group of people would be considered a sample mean population mean median split modal mean
sample mean
hich of the following is consistent with the empirical rule? 68% of all scores lie within one standard deviation of the mean. 95% of all scores lie within two standard deviations of the mean. 99.7% of all scores lie within three standard deviations of the mean. all of the above
all of the above
A researcher measures the mean time (in seconds) it takes two groups of children to complete an activity task. She finds that Group A (M = 22 seconds) completed the task more quickly than Group B (M = 36 seconds). She then computes a weighted mean for both groups combined and calculates = 26. Based on the information provided, which group had a larger sample size Group A Group B The sample size is equal in both groups. It is not possible to know this without knowing the sample size for each group.
Group A
A researcher records the following data: 4, 4, 4, 4, and 3. How would you describe the variability of the data? It is equal to zero because scores are approximately the same. It is negative because 3 is less than the other scores in the distribution. It is very small (close to 0) because scores are approximately the same. It is very large (much greater than 0) because 3 is an outlier in the data.
It is very small (close to 0) because scores are approximately the same.
The three steps for constructing a simple frequency distribution are
find the real range, find the interval width, and construct the frequency distribution
A researcher measures the amount of coffee consumed by college students while studying during the final exam week. In her study, she found that students drink 2.3±0.8 (M±SD) cups of coffee per study session. Assuming the data are normally distributed, which of the following is the most appropriate conclusion? The average student drinks less than 2.3 cups of coffee per study session. Most students drink between 1.5 and 3.1 cups of coffee per study session. Most students drink between 2.3 and 3.9 cups of coffee per study session. Most students drink between 0.7 and 2.3 cups of coffee per study session.
Most students drink between 1.5 and 3.1 cups of coffee per study session.
Which of the following is a property of the standard deviation? The standard deviation varies between - ∞ and + ∞. The standard deviation is used to describe qualitative variables. Multiplying each score times the same constant will change the standard deviation by that constant. Adding the same constant to each score will change the standard deviation by that constant.
Multiplying each score times the same constant will change the standard deviation by that constant.
A researcher records the following data for the number of complaints filed (per day) following a controversial policy change at a local business: 3, 8, 5, 0, 4, 6, 2, 1, 1, 4, 2, and 0. Is the mean equal to the median in this example? Yes. No; the median is larger than the mean. No; the mean is larger than the median. There is not enough information to answer this question.
No; the mean is larger than the median.
A researcher records the following data for the number of times an interviewer is interrupted during a series of interviews: 0, 0, 3, 2, 5, 3, 0, 8, 0, 2, 1, and 1. Is the mode equal to the median in this example? Yes. No; the median is larger than the mode. No; the mode is larger than the median. There is not enough information to answer this question.
No; the median is larger than the mode.
A researcher records the following data for the time (in seconds) it takes five rats to cross an electrical grid to obtain reinforcement on the other side: 12, 9, 13, 4, and 12. Is the mean equal to the mode in this example? Yes. No; the mode is larger than the mean. No; the mean is larger than the mode. There is not enough information to answer this question.
No; the mode is larger than the mean
To measure attraction, a researcher records the following data for the distance (in inches) between two persons sitting in a waiting room: 46, 32, 10, 23, 18, 46, and 60. Is the mode equal to the median in this example? Yes. No; the median is larger than the mode. No; the mode is larger than the median. There is not enough information to answer this question.
No; the mode is larger than the median.
A researcher measures the number of trials it takes two samples of participants to master a new task. In both samples, SS = 240. Sample A consisted of 12 participants and Sample B consisted of 18 participants. Which sample is associated with the largest variance? Sample A Sample B Both samples have the same variance. There is not enough information to answer this question.
Sample A
A researcher records the number of classroom interruptions during each of two class sessions. Which session has the largest standard deviation? Session A: 12, 15, 18, 24, and 30 Session B: 8, 10, 12, 16, and 20 Sample A Sample B Both samples have the same standard deviation.
Sample A
A researcher records the following scores for attention during a video game task for two samples. Which sample has the largest standard deviation? Sample A: 10, 12, 14, 16, and 18 Sample B: 20, 24, 28, 32, and 36 Sample A Sample B Both samples have the same standard deviation.
Sample B
State the problem with this simple frequency distribution
The class intervals overlap
A researcher reports that "the average shopper in the sample (n = 12) purchased $65.00 worth of items ( μ = $65.00) during a busy shopping day." What mistake was made is this citation? None; this citation is written appropriately. The sample mean is written using the wrong notation. The sample size is written using the wrong notation both B and C
The sample mean is written using the wrong notation.
all other things being equal, how will the value of the sample variance be different from the population variance? The sample variance will always be a smaller value than the population variance. The sample variance will always be a larger value than the population variance. The sample variance, but not the population variance, can be zero. The sample variance, but not the population variance, can be negative.
The sample variance will always be a larger value than the population variance.
Which of the following is the best explanation for why the standard deviation is almost always reported with the mean? The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation. The standard deviation is also a measure of central tendency, so it is important to report this value with the mean. The mean and standard deviation estimate basically the same thing, so these values are typically reported together. This is not true; the standard deviation is rarely reported with the mean.
The standard deviation measures the spread of scores from the mean, so it is important to know both the mean and the standard deviation.
Which of the following is true about the computational formula for variance? The computational formula will always produce the same solution as the definitional formula (give or take rounding errors). It is a short-cut method for calculating variance when the population or sample size is large. It is derived mathematically from the definitional formula. all of the above
all of the above
A professor grades 120 research papers and reports that the average score was an 80%. What do we know about the sum of the differences of these 120 scores from their mean of 80%? The sum of the differences is minimal. The sum of the differences is 80%, the same as the mean. The sum of the differences is equal to zero. It is impossible to know without knowing each of the 120 scores.
The sum of the differences is equal to zero.
Which of the following statements about a weighted mean is true. The weighted mean is always equal to the arithmetic mean. The weight mean can only be reported id the sample size is equal in each group. The weighted mean is used to compute the combined mean for two or more samples of scores in which the number of scores in each sample is disproportionate or unequal. The weighted mean is heavier than an arithmetic mean.
The weighted mean is used to compute the combined mean for two or more samples of scores in which the number of scores in each sample is disproportionate or unequal.
A researcher records the following data for the number of different food items chosen by seven participants in a buffet-style setting: 1, 6, 2, 5, 4, 3, and 7. Is the mean equal to the median in this example? Yes. No; the median is larger than the mean. No; the mean is larger than the median. There is not enough information to answer this question.
Yes
A researcher selects a sample of 6 professors, 6 students, and 6 administrators at a local school and has them rate the effectiveness of an innovative new teaching style. In this example, is it possible that the weighted mean ratings will equal the arithmetic mean for the entire sample of 18 participants? No, the weighted mean is never exactly equal to the arithmetic mean. Yes, because there are an even number of participants in each sample. Yes, because the sample sizes are equal in this example. It is not possible to know this without knowing the mean for each sample.
Yes, because the sample sizes are equal in this example.
A researcher records the following data for how participants rated the likability (on a scale from 1 = not liked at all to 7 = very likable) of an individual who blushed after making a mistake: 5, 4, 7, 6, 6, 4, 6, 7, 2, 5, and 6. Is the mode equal to the median in this example? Yes. No; the median is larger than the mode. No; the mode is larger than the median. There is not enough information to answer this question.
Yes.
A researcher records the following data for the number of dreams recalled during a night of sleep for 10 college students: 3, 2, 4, 4, 3, 1, 1, 0, 2, and 0. Is the mean equal to the median in this example? Yes. No; the median is larger than the mean. No; the mean is larger than the median. There is not enough information to answer this question.
Yes.
A researcher wants to determine how many participants will take less than 24 seconds to complete a cognitive performance task. If he constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer his question?
a cumulative frequency distribution from the bottom up
A psychologist wants to know how many of her clients continue with therapy for at least 12 days. If she constructs a frequency distribution for these data, what type of distribution would be most appropriate to answer her question?
a cumulative frequency distribution from the top down
The SIQR can be defined as the range of a distribution divided in half the IQR of a distribution plus the range a measure of half the distance between Q3 and Q1 all of the above
a measure of half the distance between Q3 and Q1
Suppose that a researcher is interested in a group of 10 million people who paid to see a movie playing in theaters. In this example, the 10 million moviegoers would be regarded as a sample of moviegoers who paid to see the movie in a theater a population of moviegoers who paid to see the movie in a theater an independent variable a dependent variable
a population of moviegoers who paid to see the movie in a theater
Which of the following will decrease the value of the mean? deleting a score below the mean adding a score below the mean adding a score exactly equal to the mean none of the above
adding a score below the mean
A reason for squaring deviations to compute SS in the numerator includes which of the following? The sum of the differences of scores from their mean is zero. The sum of the squared differences of scores from their mean is minimal. Squaring scores can be corrected easily by square rooting. all of the above
all of the above
Descriptive statistics are procedures used to summarize a set of scores or observations organize a set of scores or observations make sense of a set of scores or observations all of the above
all of the above
The mean is an appropriate measure of central tendency for data that are normally distributed data that are on an interval or ratio scale data in which the mean, median, and mode are equal all of the above
all of the above
The median is an appropriate measure of central tendency for data that are positively skewed data that are negatively skewed data that are on an ordinal scale all of the above
all of the above
The sum of the squared deviations of scores from their mean is computed the same for samples and populations is computed by squaring each deviation to avoid a zero solution in the numerator is the numerator for the sample variance and population variance all of the above
all of the above
Which of the following describes the definitional formula for variance? It is stated in terms of how variance is defined. It is computed using SS in the numerator. It is a measure of the average squared distance that scores deviate from their mean. all of the above
all of the above
The degrees of freedom for the sample variance are equal to the sample size are equal to the sample size minus one can vary between - ∞ and + ∞ both B and C
are equal to the sample size minus one
Grouped data can be distributed
as a range of values with upper and lower boundaries into intervals [all of the above]
When cumulating frequencies from the bottom up, the data are discussed in terms of
at most less than at or below all of the above
What terms refer to each of the following measures, respectively: mean, median, and mode. middle, most, and average average, middle, and most average, most, and middle most, average, and middle
average, middle, and most
A researcher records the number of children at a local school from single-, divorced-, and married-parent homes. This frequency data would be best displayed as a
bar chart
Which of the following is a type of graphical display used to summarize qualitative, discrete data?
bar chart pie chart
A researcher reports, "the average patron (n = 22) in a local bar consumed more than twice the number of drinks (per day) on weekends (M = 5.4 drinks) compared to weekdays (M = 2.3 drinks)." Although not stated directly, how do we know that the patrons in this study constitute a sample, and not a population of patrons at this local bar? We can't know for sure because this was not stated directly. The notation for a sample mean was used. The notation for sample size was used. both B and C
both B and C
Qualitative data varies by ________; quantitative data varies by ________. level; value value; level amount; class class; amount
class, amount
The procedure of converting a categorical variable to numeric values, is called: deteriorating piloting coding constructing
coding
________ are measured along a continuum at any place beyond the decimal point. continuous data discrete data qualitative data open-ended data
continuous data
________ is the variable that is believed to change in the presence of the independent variable. independent variable quasi-independent variable dependent variable
dependent variable
The use of tables and graphs to summarize data is an example of inferential statistics interpretation descriptive statistics generalization
descriptive stats
A researcher selects a sample of 24 participants and has them complete a survey on dating preferences. In this example, what are the degrees of freedom for sample variance and what does this figure represent? df = 24; it represents the number of scores that are free to vary in a sample. df = 23; it represents the number of scores that are free to vary in a sample. df = 23; dividing SS by df makes the sample variance a biased estimator of the population variance. df = 24; dividing SS by df makes the sample variance an unbiased estimator of the population variance.
df = 23; it represents the number of scores that are free to vary in a sample.
The sample variance is computed by dividing SS by ____; whereas the population variance is computed by dividing SS by ____. N; df df; n - 1 df; N n - 1; df
df; N
Recording the number of dreams recalled is an example of ________ data; whereas recording the time (in minutes) spent in a dream stage of sleep is an example of ________ data. qualitative; quantitative continuous; discrete quantitative; qualitative discrete; continuous
discrete, continous
The mean would be used to describe which of the following variables? rankings distance traveled in miles gender model of car
distance traveled in miles
Why is it important to divide by df to compute sample variance? doing so makes the sample variance an unbiased estimator of the population variance doing so ensures that the value for sample variance varies between 0 and 1 doing so minimizes the likelihood that the sample variance will be a negative value it is not important; dividing by df is optional
doing so makes the sample variance an unbiased estimator of the population variance
Each of the following are interval scale measurements, except duration of sleep (in hours) marital satisfaction ratings on a 5-point rating scale the latitude and longitude of birth for those suffering from schizophrenia the body temperature (in degrees Fahrenheit) increase during exercise
duration of sleep (in hours)
Statistical analysis allows researchers to collect data claim that an observation is scientific evaluate scientific observations study physical phenomena but not behavior
evaluate scientific observations
A researcher tests whether the dosage level of some drug (low, high) causes significant differences in health. To do this, the researcher randomly assigns rat subjects to receive a low or high dosage of the drug and records health-related measures in both groups. The type of method described is experimental quasi-experimental correlation operational
experimental
Which of the following research designs is used to determine the causes of behavior that help to explain why the behavior occurs? correlational experimental quasi-experimental all of the above
experimental
Three research methods common to research in the behavioral sciences are experimental, transferable, and correlation experimental, variable, and correlational experimental, operational, and quasi-correlational experimental, quasi-experimental, and correlational
experimental, quasi-experimental, and correlational
A therapist observes that spouses are more likely to forgive their partners for lying to them if they find out the truth from their spouse and not a third party. In this example, the dependent variable is the number of partners the spouse lying forgiveness
forgiveness
Which of the following requires the calculation of a real range?
frequency distributions for grouped data
A ________ is plotted at the midpoint of each interval, whereas a ________ is plotted at the upper boundary of each interval.
frequency polygon; ogive
When cumulating frequencies from the top down, the data are discussed in terms of
greater than at or above at least [all of the above]
A researcher summarizes a set of frequency data into five intervals. This is an example of a frequency distribution for
groped data
A graphical display for grouped frequency distributions with continuous data is called a
histogram
A researcher measures the time (in seconds) that it takes children to complete a basic reading skills task. What type of graphical display would be most appropriate for summarizing the frequency of children falling into different intervals of time?
histogram
A researcher measures the weight (in ounces) of newborn infants in the month of March. What type of graphical display would be most appropriate for summarizing the frequency of infants falling into different intervals of weight?
histogram
Which of the following is a type of graphical display used to summarize quantitative, continuous data?
histogram frequency polygon ogive [all of the above]
A researcher asks participants to estimate the calories they consume in a meal. The researcher records the following estimates: 450, 426, 310, 500, and 220. If the researcher removes the estimate of 220 (perhaps because the participant drops out of the study), then the value of the mean will decrease increase remain the same become negative
increase
Procedures that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected best describes inferential statistics sample statistics descriptive statistics population parameters
inferential stats
The range of scores between the upper and lower quartiles of a distribution is called the median quartiles percentiles interquartile range
interquartile range
The range of scores in each interval of a grouped frequency distribution is called the
interval width
Grouped data are distributed into ________, whereas ungrouped data are distributed into ________.
intervals; categories
A researcher asks adult participants to rank their top five favorite songs from their childhood. Based on the scale of measurement described, which measure of central tendency is most appropriate to describe these data? mean median mode range
median
The ________ is the middle value in a distribution of scores that are listed in numeric order. mean median mode range
median
The sum of the squared differences of scores from their mean is minimal zero negative negligible
minimal
A researcher records the hospital admission rates for coronary heart disease at 10 local hospitals. She finds that 2 different hospitals had the highest overall rates of hospital admissions. Which measure of central tendency did this researcher use to describe these data? mean median mode range
mode
The ________ is the value that occurs most often or at the highest frequency in a distribution. mean median mode range
mode
The variance and standard deviation can never be zero negative smaller than the mean larger than the mean
negative
A researcher records a sample of 30 exam scores and finds that the population variance for these data is larger than the sample variance. Is this possible? yes, the population variance is usually larger than the sample variance no, the population variance will only be larger when at least 50 scores are recorded no, the sample variance will be larger because SS is divided by degrees of freedom in the denominator of the variance formula not possible to know because the scores are not given
no, the sample variance will be larger because SS is divided by degrees of freedom in the denominator of the variance formula
An education counselor records the number of high school graduates enrolled in community colleges, four-year colleges, and universities. What scale of measurement is the type of college? nominal ordinal interval ratio
nominal
A researcher distributes frequencies into the following classes: absent, tardy, present. What type of data are distributed?
nominal data qualitative data ungrouped data [all of the above]
State the four scales of measurement in order from least informative to most informative. ordinal, nominal, interval, ratio nominal, ordinal, interval, ratio nominal, ordinal, ratio, interval ordinal, nominal, ratio, interval
nominal,ordinal, interval, ratio
A consultant ranks the five most needed areas of improvement for a local business. What scale of measurement are the rankings? nominal ordinal interval ratio
ordinal
A movie critic rates a movie on a scale from one (lowest) to four (highest) stars. What scale of measurement are the ratings? nominal ordinal interval ratio
ordinal
A cumulative percentage summary that indicates the percentage of scores at or below a given value is called a
percentile rank
The ________ is the percentage of scores with values that fall below a specified score in a distribution, is called the:
percentile rank
Each of the following is an example of quantitative data, except weight in ounces income in dollars political affiliation age in years
political affiliation
Recording whom students study with describes ________ types of data; whereas recording the number of hours spent studying per week describes ________ types of data. qualitative; quantitative continuous; discrete quantitative; qualitative discrete; continuous
qualitative; quantitative
________ data describe numeric aspects of phenomena; whereas ________ data describe nonnumeric aspects of data. quantitative; qualitative qualitative; quantitative continuous; discrete discrete; continuous
quantitative, qualitative
Three key elements of control that allow researchers to draw cause-and-effect conclusions are randomization, manipulation, and variation assignment, manipulation, and comparison/control randomization, manipulation, and comparison/control randomization, condition, and comparison/control
randomization, manipulation, and comparison/control
The median would be used to describe which of the following variables? gender ethnicity rankings brand name
rankings
To construct a pie chart, first distribute the data as
relative percentages
A researcher asks participants to estimate the height (in inches) of a statue that was in a waiting area. The researcher records the following estimates: 40, 46, 30, 50, and 34. If the researcher removes the estimate of 40 (say, due to an experimenter error), then the value of the mean will decrease increase remain the same become negative
remain the same
Researcher A measures academic preparedness as the percent correct responses on an entrance exam; Researcher B measures academic preparedness as the current class rank of students. Which researcher measured academic preparedness as discrete data? Researcher A Researcher B both researchers no researchers
researcher B
________ refer(s) to how the properties of numbers can change with different uses. measurability operational definition scales of measurement coding
scales of measurement
Which of the following distributions has the largest variability? scores: 1, 3, 6, 9, and 12 scores: 22, 24, 26, 28, and 30 scores: 2, 3, 4, 5, and 6 scores: 1, 2, 3, 4, and 5
scores: 1, 3, 6, 9, and 12
Which of the following is an example of a distribution with NO variability? scores: 3, 5, 4, 4, 5, and 3 scores: 3, 3, 3, 3, 33, and 3 scores: 1, 2, 3, 4, 5, and 6 scores: 5, 5, 5, 5, 5, and 5
scores: 5, 5, 5, 5, 5, and 5
Which of the following can be used to estimate the median? the 50th percentile of a relative percentage distribution the 50th percentile of a cumulative percentage distribution the mean the mode
the 50th percentile of a cumulative percentage distribution
A researcher records 17 scores. What is the median position of these scores? the 9th score in numeric order the average of the 9th and 10th scores in numeric order the average of the 8th and 9th scores in numeric order It's not possible to know this without the raw scores.
the 9th score in numeric order
A researcher records the number of individual instruments identified by students listening to a piece of classical music. He splits the data into quartiles and reports that students correctly identified 3 instruments at the 25th percentile, 5 instruments at the 50th percentile, and 8 instruments at the 75th percentile. What are the IQR and SIQR for these data? the IQR is 3; the SIQR is 1.5 the IQR is 2; the SIQR is 1.0 the IQR is 5; the SIQR is 2.5 There is not enough information to answer this question.
the IQR is 5; the SIQR is 2.5
A researcher records 52 scores. What is the median position of these scores? the 26th score in numeric order the average of the 26th and 27th scores in numeric order the 27th score in numeric order It's not possible to know this without the raw scores.
the average of the 26th and 27th scores in numeric order
How is the sample variance computed differently from the population variance? only one formula includes a computation for SS the calculation in the numerator is different the calculation in the denominator is different both B and C
the calculation in the denominator is different
Which of the following best describes an independent variable? the sample variable the measured behavior the manipulated variable the population variable
the manipulated variable
The fact that the sum of the differences of scores from their mean is zero best illustrates that the mean is at the center of a distribution the mean is the "balance point" of a distribution the mean is equal to zero the mean can never be negative
the mean is the "balance point" of a distribution
Which of the following best describes a dependent variable? the sample variable the measured behavior the manipulated variable the population variable
the measured behavior
An interquartile range removes the top and bottom 25% of scores in a distribution before calculating range scores above only the 75th percentile before calculating range scores below only the 25th percentile before calculating range all of the above
the top and bottom 25% of scores in a distribution before calculating range
A measure of the average squared distance of scores from the mean is called the range IQR variance sum of squares
variance
The mode can be used with the mean to describe which of the following variables? rankings gender volume in a container all of the above
volume in a container
The ________ is an arithmetic mean of a weighted or disproportionate set of scores. mean weighted mean median mode
weighted mean
#22 When would a researcher calculate a population mean? when data are measured for of a portion of individuals from a population when the sample mean it not available when data are measured for all members of a population when it is not possible to measure all data in a population
when data are measured for all members of a population
Each deviation in the numerator for variance is squared because without squaring each deviation, the solution for SS would be zero this inflates the value for variance, making it more accurate without squaring each deviation, the solution could be negative both A and C
without squaring each deviation, the solution for SS would be zero
Given the same set of data for a population and sample, would the mean for both data sets be equal? no, the population mean would be larger no, the sample mean would be larger yes, but only if the sample size equaled the population size yes, this would be true anytime both data sets are the same
yes, this would be true anytime both data sets are the same
Which of the following is not a symbol used with samples: x M μ n
μ
The population mean is symbolized as ________, whereas the sample mean is symbolized as ________. μ; M M; μ n; N N; n
μ; M
