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EPPP 1664 > Statistics > Flashcards

Statistics Flashcards

1
Q

This scale of measurement divides variables into unordered categories. Examples of this would be gender, eye color, place of birth, etc.

a. Nominal scale
b. Ordinal scale
c. Interval scale
d. Ratio cale

A

a

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2
Q

This scale of measurement has the property of equal intervals between successive points on the measurement scale. IQ tests use this type of measurement.

a. Nominal scale
b. Ordinal scale
c. Interval scale
d. Ratio scale

A

c

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3
Q

This scale of measurement is the most mathematically complex of the four scales of measurement. It has the properties of order and equal intervals as well as the property of an absolute zero point. Examples include temperature when measured on a Kelvin scale, number of calories consumed, number of correct items on a test, and reaction time in seconds.

a. Nominal scale
b. Ordinal scale
c. Interval scale
d. Ratio scale

A

d

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4
Q

When a distribution is more “peaked” than the normal distribution, it is said to be:

a. skewed
b. leptokurtic
c. normal
d. platykurtic

A

b

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5
Q

When a distribution is flatter than the normal distribution, it is said to be:

a. skewed
b. leptokurtic
c. normal
d. platykurtic

A

d

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6
Q

In a ____________ distribution, over 50% of the scores fall on one side of the distribution:

a. skewed
b. leptokurtic
c. normal
d. platykurtic

A

a

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7
Q

When 50% or more of the scores are concentrated on the positive side of the distribution with only a relatively few scores in the negative side (tail), the distribution is said to be:

a. Positively skewed
b. Negatively skewed
c. Normally distributed
d. Leptokurtic

A

b

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8
Q

When 50% or more of scores are concentrated in the negative side of the distribution with only a relatively few scores in the positive side (tail), the distribution is called:

a. Positively skewed
b. Negatively skewed
c. Normally distributed
d. Leptokurtic

A

a

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9
Q

The score or category that occurs most frequently in a set of data

A

Mode

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10
Q

A distribution with two modes is called:

A

bimodal

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11
Q

This is the score that divides a distribution in half when the data have been ordered from low to high

A

Median

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12
Q

The arithmetic average

A

mean

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13
Q

One advantage of the ______ is that, of the three measures of central tendency, it is the least susceptible to sampling fluctuations.

A

mean

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14
Q

Order of measures of central tendency in a positively skewed distribution:

A

Mode, Median, Mean

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15
Q

Order of measures of central tendency in a negatively skewed distribution:

A

Mean, Median, Mode

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16
Q

This is calculated by subtracting the lowest score in the distribution from the highest score:

a. Variance
b. Standard deviation
c. Range
d. Mean

A

c

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17
Q

The _____________ is equal to the square root of the variance.

a. Mode
b. Standard deviation
c. Range
d. Mean

A

b

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18
Q

If a distribution of IQ scores has a mean of 100 and a variance of 225, its standard deviation is equal 15. Assuming that the population distribution is normal, this means that, in the population, about _____ percent of people have IQ scores between 85 and 115. about _____ percent of people have scores between 70 and 130; and about ____ perceent have scores between 55 and 145.

a. 60, 80, 90
b. 65, 92, 95
c. 50, 85, 98
d. 68, 95, 99

A

d

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19
Q

The numerator of the __________ is called the sum of squares, which is short for the “sum of squared deviation scores.”

A

variance

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20
Q

This is calculated by stubtracting the mean from each score tto obtain deviation scores, squaring each deviation score, and then summing the squared deviation scores

A

sum of squares (related to variance)

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21
Q

When a distribution is normal _______ of the scores fall between scores that are plus or minus one standard deviation from the mean; ________ of the scores fall between the scores that are plus and minus two standard deviations from the mean; and ______ of the scores fall between the scores that are plus and minus three standard deviations from the mean.

A

68.26%; 95.44%; 99.72%

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22
Q

An inferential statistical test enables an investigator to determine the probability of obtaining a sample with a particular value by comparing the obtained sample value to an appropriate ___________ distribution.

A

sample

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23
Q

This provides an estimate of the extend to which the mean of any one sample randomly drawn from a population can be expected to vary from the population mean as the result of sampling error.

A

standard error of the mean

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24
Q

What are the three predictions of the Central limit theorem?

A

Regardless of the shape of the distribution of inndividual scores in the population, as the sample size increases, the sampling distribution of the mean is equal to the population mean.

The mean of the sampling distribution of the mean is equal to the population mean.

The standard deviation of the sampling distribution of the mean is equal to the population standard deviation dividied by the square root of the sample size.

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25
Q

This implies that the independent variable does not have an effect on the dependent variable

A

null hypothesis

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26
Q

Implies that the independent variable has an effect on the dependent variable

A

Alternative hypothesis

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27
Q

The ____________, or “region of unlikely values,” lies in one or both tals of the sampling distribution and contains the sample values that are not likely to occur simply as the result of sampling error. The ______________, or “region of likely values,” lies in the central portion of the sampling distribution and consists of the values that are likely to occur as a consequence of sampling error only.

A

rejection region (think rejecting the null hypothesis); retention region (think retaining the null hypothesis)

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28
Q

The size of the rejection region is defined by ________, or the level of significance.

A

alpha

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29
Q

If alpha is .05, then ____% of the sampling distribution represents the rejection region and the remaining _____% represents the retention region.

A

5;95

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30
Q

When the results of an inferential statistical test indicate that the obtained sample statistic lies in the ______________ of the sampling distribution, the study’s results are said to be statistically significant.

A

rejection region

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31
Q

It is the alternative hypothesis that determines whether a one- or a two-tailed test should be conducted. A __________ test is used when the alternative hypothesis is nondirectional, while a ___________ test is used when an alternative hypothesis is directional.

A

two-tailed; one-tailed

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32
Q

Occurs when an investigator rejects a true null hypothesis; states that there is an effect when there is not

A

Type I error

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33
Q

Occurs when an investigator retains a false null hypothesis; says that there was no effect when there actually was

A

Type II error

34
Q

The probability of making a __________ error is equal to alpha.

A

Type I

35
Q

The probability of make a ________ error is equal to betta.

A

Type II

36
Q

A _________ error is more likely when the value of alpha is low, when the sample size is small, and when the independent variable is not administered in sufficient intensity.

A

Type II

37
Q

When a statistical test enables an experimenter to reject a false null hypothesis, the test is said to have ________________.

A

statistical power

38
Q

How can researchers maximize power?

A

Increase alpha
Increase sample size
Increase the effect size
Minimizing error
Using a one-tailed tests when appropriate
Using a parametric test (t-test or ANOVA)

39
Q

Refers to the ability to reject a false null hypothesis and is affected by the size of alpha.

A

Power

40
Q

Refers to the certainty a researcher has about the decision he or she has already made about the null hypothesis.

A

confidence

41
Q

An experimenter has more confidence that his or her decision to reject the null hypothesis was correct when alpha is ________.

A

small

42
Q

For children with ADHD, an academic achievement test has a mean of 40 and a standard deviation of 8. Assuming that the distribution of scores is normally-shaped, you can conclude that 16% of children obtained scores below a score of:

a. 24
b. 32
c. 40
d. 48

A

b

43
Q

In a negatively skewed distribution of scores that range form 0 to 100:

a. the median is greater than the mean
b. the median is less than the mean
c. the mean is greater than the mode
d. the median is greater than the mode

A

a. In a negatively skewed distribution, most scores are “piled up” in the positive end and a few scores lie in the negative end. Because the mean is more sensitive to the value of all scores, it is lower than the median or the mode

44
Q

If an experimenter compares the difference between two means to assess the effects of an IV on a DV, she will have the most confidence in her results if they are statistically significant at the ____ level of significance:

a. .10
b. .50
c. .05
d. .01

A

d

45
Q

To increase power:

a. increase the value of beta
b. increase the value of alpha
c. reduce the value of alpha
d. reduce the value of alpha and increase the value of beta

A

b

46
Q

Increasing the level of significance (alpha) from .01 to .05 will:

a. increase the probability of a Type I and a Type II error
b. decrease the probability of a Type I and a Type II error
c. increase the probability of Type I error but decrease the probability of a Type II error
d. decrease the probability of a Type I error but increase the probability of a Type II error

A

c. Increasing the magnitude of alpha makes it easier to reject the null hypothesis. Consequently, it increases the chance of rejecting a true null hypothesis (Type I error) and decreases the chance of retaining a false null hypothesis (Type II error)

47
Q

The standard error of the means decreases as:

a. the population standard deviation increases and the sample size increases
b. the population standard deviation increases and the sample size decreases
c. the population standard deviation decreases and the sample size decreases
d. the population standard deviation decreases and the sample size increases

A

d

48
Q

According to the Central Limit Theorem, the shape of the sampling distribution of means:

a. is always normal
b. is normal only when the population distribution is normal
c. approaches normal as the number of samples increases regardless of the shape of the population distribution
d. approaches normal as the size of samples increases regardless of the shape of the population distribution

A

d. The Central Limit Theorem predicts that the sampling distribution increasingly approaches normal as the sample size increases

49
Q

A _____________ test is used when the data being analyzed represent an interval or ratio scale of measurement and when two assumptions have been met: 1) In the population from which the sample was drawn, the scores on the variable are normally distributed; 2) There is homoscedacity, which means that the population variances are equal

A

parametric

50
Q

Types of parametric tests

A

T-tests; ANOVA; MANOVA

51
Q

Nonparametric Tests

A

Chi-square; Mann-Whitney U test; Wilcoxon matched pairs test; Kruskal-Wallis test

52
Q

These types of tests are used to analyze data collected on variables that have been measured on a nominal or ordinal scale

A

Nonparametric tests

53
Q

The number of values or categories in a distribution that are “free to vary” given that certain values or categories are known or fixed. Calculated from the total number of subjects (N-1) or categories (C-1).

A

degrees of freedom

54
Q

This type of test is used to analyze the frequency of observations in each category (level) of a nominal variable (or other variable that is being treated as a nominal variable). Would be appropriate for comparing the number of people who prefer one of four political candidates or comparing the number of managerial and non-managerial employees who say that either physiological,, safety, social, self-esteem, or self-actualization needs are most important:

a. t-test
b. Chi-square test
c. Mann-Whitney U Test
d. Kruskal-Wallis Test

A

b

55
Q

These tests are used to analyze data when a study includes one independent variable with two levels and the data to be analyzed are reported in terms of ranks.

A

Mann-Whitney U test and the Wilcoxon matched-pairs test

56
Q

The Mann-Whitney U test is appropriate when the two groups are _____________, while the Wilcoxon test is used when the groups are ______________.

A

independent; correlated

57
Q

This type of test is similar to the Mann-Whitney U test but can be used when a study includes two or more independent groups and the data to be analyzed are ranks.

A

Kuskal-Wallis test

58
Q

The t-test for a single sample is appropriate or comparing an obtained _____________ to a known ______________.

A

group/sample mean; population mean

59
Q

The various forms of the t-test are all used to compare two:

a. means
b. variances
c. populations
d. samples

A

a

60
Q

The t-test for _________________ is used to compare the means obtained by subjects in two unrelated groups.

A

independent samples

61
Q

This scale of measurement divides observations into categories and provides information on the order of those categories. When using this scale, it is possible to say that one person has more or less of the characteristic being measured. Examples this would be ranks and Likert-scales. One limitation is that they do not lend themselves to determining just how much difference there is between scores.

a. Nominal scale
b. Ordinal scalle
c. Interval scale
d. Ratio scale

A

b

62
Q

The t-test for ____________ is used to compare two means when groups are related.

A

correlated

63
Q

This test would be used when a researcher wanted to compare two or more means:

a. Correlated t-test
b. ANOVA
c. MANOVA
d. Kruskal-Wallis test

A

b

64
Q

This type of test is used when a study includes one IV and two or more independent groups and one DV that is measured on an interval or ratio scale.

a. Correlated t-test
b. One-Way ANOVA
c. Factorial ANOVA
d. t-test for independent samples

A

b

65
Q

This test is the appropriate statistical test when a research study includes two or more independent variables.

a. Correlated t-test
b. One-Way ANOVA
c. Factorial ANOVA
d. t-test for independent samples

A

Factorial ANOVA

66
Q

This statistical test can be used when a study includes one or more independent variables and two or more dependent variables that are each measured on an interval or ratio scale.

A

MANOVA

67
Q

The effects of an extraneous variable can be statistically removed by using this type of test.

A

ANCOVA

68
Q

Cohen’s d and eta squared can both be used as measures of _______________.

A

effect size

69
Q

Summarizes the degree of association between variables with a single number

A

correlation coefficient

70
Q

The most commonly used coefficient with interval and ratio data

A

Person r

71
Q

Dr. Tas obtains SAT scores from a sample of 30 high school seniors following their participation in a workshop designed to improve SAT scores. The best statistical technique for analyzing the results of this study if Dr. Tas wants to compare the obtained mean SAT score to the national mean is which of the following:

a. t-test for a single sample
b. t-test for independent samples
c. one-way ANOVA
d. Wilcoxon test

A

a

72
Q

The chi-square test would not be appropriate for analyzing data collected from which of the following studies:

a. a study conducted to determine if there is a difference in the number of males and females who either support, do not support, or have no opinion about gun control.
b. a study designed to determine if the number of males and females who act in a pro-social way in an emergency situation is different before and after participation in a special workshop
c. a study designed to determine if there is any difference in the proportion of people who have received a diagnosis of either Bipolar Disorder, Mixed, Bipolar Disorder, Manic, or Bipolar Disorder, Depressed who do and do not have one parent, both parents, or neither parent with an affective disorder.
d. a study conducted to compare the number of people who, after seeing a film on environmental waste, plan to recycle consistently, recycle occasionally, or not recycle and who say they either would or would not be willing to pay more for recycled products

A

b

73
Q

Sixty subjects are randomly assigned to one of three groups and the average IQ score of each group is calculated. If a one-way ANOVA is used to compare the mean scores of the three groups, you would expect the resulting F-ratio to:

a. be equal to 0
b. be equal to 1.0
c. be greater than 1.0
d. be equal to -1.0

A

b. The F-ratio is calculated by dividing “mean square between” by “mean square with.” Mean square between is a measure of variability due to the effects of error plus the independent variable; mean square within is a measure of variability due to the effete of error only. In the situation described in this question, there is no independent variable, so the F-ratio will simply be a measure of error divided by error, which should equal a value very close to 1

74
Q

The t-test for dependent samples is used to analyze the data collected in a study involving 36 subjects who had been matched on an extraneous variable before being assigned to a treatment group. The degrees of freedom for this group are:

a. 36
b. 35
c. 18
d. 17

A

d

75
Q

A researcher will use trend analysis to analyze the data she has collected in a research study when:

a. the research design is quasi experimental
b. the dependent variables are correlated
c. the independent variable is quantitative
d. the research design is longitudinal

A

c. Trend analysis is a type of analysis of variance that can be used when the IV is quantitative. It allows the researcher to determine whether there is a linear or nonlinear effect on the IV on the DV

76
Q

A high school counselor uses a battery of tests to help high school juniors and seniors choose a college major. Which of the following multivariate techniques would be most helpful in this situations:

a. multiple regression
b. multiple cutoff
c. discriminant analysis
d. parital correlation

A

c. The appropriate multivariate technique used when the criterion is measured on a nominal scale is discriminant analysis

77
Q

If the correlation between Test A and Test B is -.42, this means that approximately _____% of variability in Test A scores is shared in common with Test B scores:

a. 17
b. 32
c. 42
d. 58

A

a. To obtain a measure of shared variability, the correlation coefficient is squared: -.42 squared = .17 (or 17%)

78
Q

You are interested in correlating gender of respondent with attitude toward abortion. Assuming your attitude measure represents an interval scale, which of the following correlation techniques would you use:

a. point biserial
b. Pearson r
c. phi coefficient
d. contingency coefficient

A

a. The point biserial correlation coefficient is the appropriate coefficient when one variable represents a true dichotomy and the other variable is measured on either an interval or ratio scale.

79
Q

When using path analysis, you are:

a. employing two or more predictors to estimate status on a single continuous criterion
b. determining the causal relationships among a set of observed and latent variables
c. confirming a model involving one-way causal flow between a set of observed variables
d. developing a model involving one- and two-way causal flow between a set of observed variables and latent traits

A

c

80
Q

Eta is used to:

a. assess statistical significance
b. measure a curvilinear relationship
c. normalize a non-normal distribution
d. make predictions with multiple predictors

A

b. Eta is a type of correlation coefficient. it is used to assess the degree of association between continuous variables when their relation is nonlinear

EPPP 1664 (16 decks)

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