CH. 13

frequency

# of times a category, a score, or range of scores occurs

left, negative skew

- long tail on left side - mean and median on left side - mode > median > mean - low values are likely to be the outliers - values more spread out on the left

right, positive skew

- long tail on right side - mean and median on right side - mean > median > mode - high values are likely to be the outliers - values more spread out on the right

central tendency

A single statistical score near the center of a distribution that meaningfully represents the distribution

Which measure of reliability is used to estimate the average correlation for every possible way that a measure can be split in half? a. Cronbach's alpha b. Cohen's kappa c. Solomon's beta d. Central tendency

a. Cronbach's alpha

In a histogram, ________ are distributed along the horizontal axis and the ________ are listed along the vertical axis. a. continuous data; frequency of data b. discrete data; sample means c. continuous data; variability of scores d. discrete data; frequency of data

a. continuous data; frequency of data

Histograms are used to summarize ________ data; bar charts and pie charts are used to summarize ________ data. a. continuous; discrete b. discrete; continuous c. descriptive; inferential d. inferential; descriptive

a. continuous; discrete

The mean is used for data that can be described in terms of the ________ that scores deviate from the mean. a. distance b. category c. constant d. significance

a. distance

The larger the sample variance, the ________ that scores deviate from the mean on average. a. farther b. closer c. either a or b d. neither a or b

a. farther

In a frequency distribution table, list each score or range of scores in one column and: a. list corresponding frequencies for each score or range of scores in a second column. b. list the mean and variance for each score or range of scores in a second column. c. list the outcome of a test statistic for each score or range of scores in a second column. d. list the mean and range for each score or range of scores in a second column.

a. list corresponding frequencies for each score or range of scores in a second column.

By convention, we use a bar graph when the groups on the x-axis (horizontal axis) are represented on a ________ scale; we use a line graph when the groups on the x-axis are represented on an ________ scale. a. nominal or ordinal; interval or ratio b. interval or ratio; nominal or ordinal c. ordinal or interval; nominal or ratio d. nominal or ratio; ordinal or interval

a. nominal or ordinal; interval or ratio

The sum of the squared deviations of scores from the mean and the numerator of the sample variance formula, is called: a. sum of squares. b. degrees of freedom. c. sample mean. d. standard deviation.

a. sum of squares. (in the numerator)

standard deviation

average distance from the mean square root of variance corrects for squaring the deviation SD = s^2 = square root of SS/d(F)

variance

average square difference that scores deviate from the mean (they would sum to zero if they weren't squared) then divided by degrees of freedom (number of scores -1) to get the average squared distance from the mean s^2 = SS/d(f) where d(f) = n-1

Cohen's kappa varies between: a. -1 and +1. b. 0 and 1. c. 0 and . d. -1 and 0.

b. 0 and 1.

Cronbach's alpha varies between: a. -1 and +1. b. 0 and 1. c. 0 and . d. -1 and 0.

b. 0 and 1.

Which of the following data sets is associated with a mean value that is larger than both the median and mode? a. 3, 2, 5, 4, 8, 5, and 8 b. 2, 4, 8, 7, 6, 2, and 0 c. 1, 1, 3, 2, 4, 6, and 7 d. 1, 3, 3, 2, 3, 4, and 5

b. 2, 4, 8, 7, 6, 2, and 0

A researcher records a large sample of data with a mean equal to 36 and a standard deviation equal to 1.5. If the data are normally distributed, then using the empirical rule which of the following gives the closest estimate for the percent of data that falls between scores 33 and 39. a. At least 68% b. At least 95% c. At least 99.7% d. At least 100%

b. At least 95%

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? a. Mean b. Median c. Mode d. Range

b. Median

Which of the following words best relates to descriptive statistics? a. Infer b. Summarize c. Explain d. Predict

b. Summarize

Which of the following statements describes the formula for computing sample variance? a. The sum of all scores divided by the number of scores summed. b. The sum of squares divided by the degrees of freedom for sample variance. c. The sum of all scores divided by the degrees of freedom for sample variance. d. The mean difference divided by the standard error for the sample variance.

b. The sum of squares divided by the degrees of freedom for sample variance.

A graphical display used to summarize the frequency of continuous data that are distributed in numeric intervals using bars connected at the upper limits of each interval, is called: a. bar chart. b. histogram. c. pie chart. d. central tendency.

b. histogram.

A measure of variability for the average distance that scores in a sample deviate from the sample mean, is called: a. sample variance. b. sample standard deviation. c. sum of squares. d. degrees of freedom.

b. sample standard deviation.

A measure of variability for the average squared distance that scores in a sample deviate from the sample mean, is called: a. mean. b. variance. c. standard deviation. d. mode.

b. variance.

what graph should be used for: groups represented on a nominal or ordinal scale

bar graph

Which type of graph is used to summarize group means? a. Bar graph b. Line graph c. Bar and line graphs d. Tabular graph

c. Bar and line graphs

Which measure is used when trying to identify the reliability of a measure? a. Cohen's kappa b. Cronbach's alpha c. Both Cohen's kappa or Cronbach's alpha d. Neither Cohen's kappa or Cronbach's alpha

c. Both Cohen's kappa or Cronbach's alpha

A measure of interrater reliability that estimates the level of agreement between two raters, while taking into account the probability that the two raters agree by chance or error, is called: a. central tendency. b. Cronbach's alpha. c. Cohen's kappa. d. partial test statistic.

c. Cohen's kappa.

A scatter plot is specifically used to describe what type of data? a. Scattered data b. Group means c. Correlated data d. Group variance

c. Correlated data

The sample mean is appropriately used to describe data on which scale of measurement? a. Nominal and ordinal b. Ordinal and interval c. Interval and ratio d. Ordinal and ratio

c. Interval and ratio

1. How is the sample standard deviation is computed? a. It is equal to the sample variance squared b. It is equal to the mean in a population c. It is the square root of the sample variance d. It is the sum of all scores divided by degrees of freedom

c. It is the square root of the sample variance

If a set of data are normally distributed with at least 68% of scores falling between scores 16.5 and 19.5. If these values mark the first standard deviation from the mean, then what are the values of the mean and standard deviation in this normal distribution? a. Mean = 16.5, standard deviation = 1.5 b. Mean = 16.5, standard deviation = 3.0 c. Mean = 18.0, standard deviation = 1.5 d. Mean = 18.0, standard deviation = 3.0

c. Mean = 18.0, standard deviation = 1.5

A researcher records the hospital admission rates for coronary heart disease at 10 local hospitals. She finds that two different hospitals had the highest overall rates of hospital admissions. Which measure of central tendency did this researcher use to describe this data? a. Mean b. Median c. Mode d. Range

c. Mode

Which of the following is a common way in which researchers analyze a dataset? a. Researchers can describe data b. Researchers can make decisions about how to interpret data c. Researchers can describe data and make decisions about how to interpret data d. None of the above

c. Researchers can describe data and make decisions about how to interpret data

What is the rule for normally distributed data that states that at least 99.7% of data fall within 3 SD of the mean; at least 95% of data fall within 2 SD of the mean; and at least 68% of data fall within 1 SD of the mean? a. The absolute rule b. The distributional rule c. The empirical rule d. The golden rule

c. The empirical rule

A researcher records the following scores on a behavioral assessment: 12, 20, 9, 12, 32, 18, 23, 10, and 17. Which of the following statements is true? a. The median is larger than the mean. b. The mode is larger than the median. c. The mean is larger than the median. d. The mean and mode are larger than the median.

c. The mean is larger than the median.

The formula for the degrees of freedom for sample variance is: a. sum of squares minus one. b. sample mean minus one. c. sample size minus one. d. sample variance minus one.

c. sample size minus one.

Each bar in a bar chart represents: a. the variability of scores in a category. b. the mean or average for each count. c. the frequency of a score or category. d. the separation or distance between bars in the chart.

c. the frequency of a score or category.

The name empirical rule comes from the word empiricism, meaning: a. to educate. b. to distribute. c. to observe. d. to approximate.

c. to observe.

outliers ( can | cannot ) significantly alter mean

can

variability ( can | cannot ) be negative

cannot no variability = 0

A researcher records a sample mean equal to 1.2. If 99.7% of all scores fall between scores 0.6 and 1.8, then using the empirical rule, what is the standard deviation for these data? a. 1.2 b. 0.6 c. 0.4 d. 0.2

d. 0.2

Using the Chebyshev theorem, we can determine that at least 99% of all scores will fall within __ SD of the mean for a distribution with any shape. a. 3 b. 6 c. 9 d. 10

d. 10

The empirical rule states that at least ____% of data fall within 1 SD of the mean, whereas at least ____% of data fall within 3 SD of the mean. a. 95; 99.7 b. 68; 95 c. 99.7; 68 d. 68; 99.7

d. 68; 99.7

A researcher wants to analyze the reliability of a survey that consists of multiple items used to measure the same construct to determine if all items measure the same construct. Which measure of reliability should the researcher compute? a. Central tendency b. Cohen's kappa c. Solomon's beta d. Cronbach's alpha

d. Cronbach's alpha

A measure of internal consistency that estimates the average correlation for every possible way that a measure can be split in half, is called: a. central tendency. b. sample variance. c. Cohen's kappa. d. Cronbach's alpha.

d. Cronbach's alpha.

Cohen's kappa is used to measure which type of reliability? a. Ecological reliability b. Test-retest reliability c. Internal consistency d. Interrater reliability

d. Interrater reliability

Which of the following is a measure of variability? a. Mean b. Variance c. Standard deviation d. Variance and standard deviation

d. Variance and standard deviation

A graphical display used to summarize the frequency of discrete and categorical data using bars to represent each frequency, is called: a. line graph. b. histogram. c. pie chart. d. bar chart.

d. bar chart.

A clear presentation of the data is necessary because of all of the following except: a. can allow for a more meaningful arrangement of the data. b. can clarify what patterns were observed in a dataset at a glance. c. allows the reader to critically evaluate the data you are reporting. d. clearly indicates significance for all data.

d. clearly indicates significance for all data.

The median is an appropriate measure of central tendency for all of the following except: a. data that are positively skewed. b. data that are negatively skewed. c. data that are on an ordinal scale. d. data that are on a nominal scale.

d. data that are on a nominal scale.

The mode is an appropriate measure of central tendency for all of the following except: a. data that are bimodal. b. use with other measures of central tendency. c. data that are on a nominal scale. d. data that are on an ordinal scale.

d. data that are on an ordinal scale.

A graphical display of discrete data points used to summarize the relationship between two correlated variables, is called: a. line graph. b. bar chart. c. pie chart. d. scatter plot.

d. scatter plot.

A frequency distribution table can summarize the frequency of all of the following except: a. continuous data. b. discrete data. c. categorical data. d. significant data.

d. significant data.

The sample mean is all of the following except: a. a measure of central tendency. b. the balance point of a distribution. c. used to summarize interval and ratio data. d. used to summarize nominal data.

d. used to summarize nominal data.

Statistical measures for the dispersion or spread of scores in a distribution or dataset, is called: a. measurability. b. central tendency. c. sampling variability. d. variability.

d. variability.

The separation between bars in a bar chart reflects the separation or "break" between the ________ being summarized. a. whole numbers b. discrete data c. categories d. whole numbers, discrete data, and categories

d. whole numbers, discrete data, and categories

histogram

depicts continuous data in numeric intervals x-axis: interval of continuous scores (or groups of continuous scores) y-axis: frequency of scores

bar graph

depicts nominal or discrete data like a histogram (x = groups represented by whole #s or categories; y = frequencies of whole #s or categories) separation b/w bars = break between whole numbers or categories; non-continuous

variation

describes how widely data are spread out about the center of a data set

range

difference between lowest and highest values

the empirical rule

for normally distributed data, 68% of scores fall within one SD of the mean, 95% fall within two SDs of the mean, and 99.7% fall within three SDs of the mean

pie chart

graphical display of nominal or discrete data (proportions) in the form of a circle

sample mean best used with _____ data

interval or ratio

what graph should be used for: groups represented on an interval or ratio scale

line graph

negative correlations reflected with a descending line

looks like a slope of -1

positive correlation with ascending line

looks like slope of +1

in a normal distribution, ___________ are all the same value at the center

mean, median, and mode

central tendency for skewed data

median

median

middle value in distribution of scores listed in numerical order

mode best used with ___________ distributed data

modal (rarely used to describe a distribution)

central tendency for categorical data

mode

central tendency for data with two modes

mode

mode is best used with ______ data

nominal

mean best used with ___________ distributed data

normally distributed data - scores are symmetrically distributed around the mean

median is best used with ______ data

ordinal

IQR

range of scores in a distribution between first and third quartiles (3 to 6 or 3)

median best used with ___________ distributed data

skewed distributed data

range is not informative in...

small samples with large outliers

sample mean

sum scores in a distribution and divide by the scores

frequency table

used to summarize data