Statistical Analysis (210)

Four students have applied to a special program and only one can be accepted. They have taken a battery of 12 tests and all have exactly the same average score. The standard deviation of their test scores are: Student A = 3.12, Student B = 0.27, Student C = 13.45, Student D = 6.45. If consistency of performance is a criteria for acceptance, which of the four students should be selected?

B

The grades on a final exam for a statistics class are as follows: 25% As, 35% Bs, 30% Cs, 9% Ds and 1% Fs. The modal grade of the class is

B

City A (population = 1567 people) had 34 auto thefts last year. City B (population = 34,567) had 40 auto thefts in the same time period and City C (population = 156,980) had 70 auto thefts. Which city had the highest RATE of auto theft?

City A

What is the probability that a randomly selected case from a normally distributed distribution will have a score between -1.00 and the mean? A.0.34 B.0.16 C.0.50 D.0.86

0.34

The average homicide rate for the cities and towns in a state is 10 per 100,000 population with a standard deviation of 2. If the variable is normally distributed, what is the probability that a randomly selected town will have a homicide rate greater than 8? A.0.34 B.0.68 C.0.84 D.0.01

0.84

The probability of getting a 1 in a single toss of a six sided die would be A.2 to 1. B.60 to 1. C.1 in 6. D.impossible to estimate with the information given.

1 in 6.

The area between the mean and a Z score of +1.50 is 43.32%. This score is less than of the scores in the distribution. A.43.32% B.6.68% C.3.32% D.93.32%

6.68%

What is the median of the following set of eleven grades? 55 60 62 67 70 72 75 76 77 85 95

72

If distribution A and distribution B have the same mean but A has a larger standard deviation, we may conclude that A.the medians of both distributions would be the same. B.distribution B has a range of 0. C.A has a greater degree of dispersion. D.distribution B displays more variety.

A has a greater degree of dispersion.

Assuming a normal distribution of 1000 cases, how many cases will be within ± 1 standard deviations of the mean? A.At least 500 B.About 3 C.About 680 D.It is impossible to estimate

About 680

The mean on a standardized test is 100 and the standard deviation is 35. Your score is 65. What percentage of the scores were higher than yours? A.About 84% B.No more than 50% C.About 34% D.About 16%

About 84%

When an empirical normal distribution of scores is standardized A.the mean will become 0. B.the standard deviation will become 1. C.each score will be converted to a Z score. D.All of the above.

All the above

If male and female college students work an average of 15 hours per week during the school year and the standard deviation is 5.4 for male students and 2.3 for female students, what may we conclude? A.Males are more heterogeneous on this variable. B.Females are more heterogeneous on this variable. C.The median number of hours worked is the same. D.The modal number of hours worked is the same.

Males are more heterogeneous on this variable.

Which measure of central tendency is like a fulcrum that exactly balances all of the scores? A.Mode B.Median C.Mean D.None of the above

Mean

Variables measured at the ordinal level are limited to which of the following mathematical operations? A.Addition and subtraction B.Multiplication C.Ranking cases as higher or lower, more or less D.Counting the number of cases per category

Ranking cases as higher or lower, more or less

The income of a sample has been measured in dollars per year. Which of the following would be the preferred measure of the dispersion for this variable? A.The index of qualitative variation B.The average deviation C.The quartile deviation D.The standard deviation

The standard deviation

Which measure of dispersion is most important and most commonly used in social science research? A.The range B.The average deviation C.The median D.The standard deviation

The standard deviation

When constructing a frequency distribution, the number of class intervals, in general, should be A.more than 20. B.about 10. C.only 2. D.the same as the number of cases.

about 10

On all normal curves the area between the mean and +1 standard deviation will be A.about 34% of the total area. B.about 68% of the total area. C.about 95% of the total area. D.about 99% of the total area.

about 34% of the total area?

On all normal curves the area between the mean and ± 1 standard deviation will be A.about 34% of the total area. B.about 68% of the total area. C.50% of the total area. D.99.9% of the total area.

about 68% of the total area.

In the language of science, a variable that is thought to be causal is called A.an independent variable. B.a hypothetical variable. C.a primary variable. D.a dependent variable.

an independent variable.

If a student scored in the 93rd percentile on an exam, that means that A.ninety three percent of students who took the exam scored lower than them. B.seven percent of students who took the exam scored higher than them. C.neither of these choices are correct. D.both of these choices are correct.

both of these choices are correct

When measures of central tendency and dispersion are presented in the literature, the number of cases may vary A.the researchers only used a subset of their sample for convenience purposes. B.cases were missing values for that variable. C.the variable in those cases was measured at a different level. D.none of these choices are correct.

cases were missing values for that variable.

The median defines "central tendency" in terms of the A.most common score. B.central case. C.most likely or probable score. D.largest score.

central case

The crude birth rate of a city that has 250 births in a year and a population of 7500 would be found by using which of the following? A.crude birth rate = (250/7500) x 1000 B.crude birth rate = 7500/250 C.crude birth rate = (1000/7500) x 250 D.crude birth rate = (250/1000) x 7500

crude birth rate = (250/7500) x 1000

If a researcher summarizes the age of 1,000 people by calculating the average age, she is using A.a qualitative technique. B.an incorrect hypothesis. C.data reduction. D.non-empirical reasoning.

data reduction

A frequency distribution should reflect a balance of A.detail and conciseness. B.time and money. C.questions and answers. D.elegance and symmetry.

detail and conciseness.

The distances between the scores and the mean are called A.deviations. B.differences. C.ranges. D.summations.

deviations

A nominal-level variable like marital status or gender is always A.discrete. B.continuous. C.ordinal. D.dependent.

discrete

To find the ratio of smokers to non-smokers, you would A.divide the number of non-smokers by the number of smokers. B.add them together and divide by the number of smokers. C.divide the number of smokers by the number of non-smokers. D.multiply the number of smokers by the total number of people.

divide the number of smokers by the number of non-smokers

When constructing frequency distributions for variables measured at the interval-ratio level, approximate interval size (or interval width) can be found by A.dividing sample size (N) by 10. B.multiplying the number of categories by the lowest score C.dividing the range by the sample size (N). D.dividing the range (R) by the number of categories (k).

dividing the range (R) by the number of categories (k).

A police department reports that the number of reported rapes in their jurisdiction increased by 100% over the past decade. This means that the number of reported rapes today is A.double the number 10 years ago. B.actually about the same as 10 years ago. C.equal to the number 10 years ago plus 50%. D.triple the number 10 years ago.

double the number 10 years ago.

In the normal curve, the mean is A.greater than the median. B.greater than the mode. C.less than the median. D.equal to the median and mode.

equal to the median and mode.

The Z scores of two tests scores are + 1.2 and + 1.5. To obtain the area between these scores A.subtract the Z scores and find the area of the difference in the Z score table. B.find the area between each score and the mean in the Z score table and then subtract the smaller area from the larger area. C.find the area between each score and the mean in the Z score table and then subtract the difference between them from 100%. D.find the area beyond each score in the Z score table and subtract the difference between the areas from the mean.

find the area between each score and the mean in the Z score table and then subtract the smaller area from the larger area.

The area between two negative Z scores can be found by A.adding the Z scores and finding the area below the total Z score. B.subtracting the Z scores and finding the total area above the total Z score. C.finding the area between each Z score and the mean and subtracting the smaller area from the larger. D.finding the area between each Z score and the mean and adding the areas.

finding the area between each Z score and the mean and subtracting the smaller area from the larger.

A theory differs from an hypothesis in that it is more A.testable. B.specific. C.general. D.concrete.

general?

In a boxplot, an outlier is defined as a score that is A.greater than 1.5 times the height of the box. B.less than 1.5 times the height of the box. C.greater than 1.25 times the height of the box. D.greater than 0.75 times the height of the box.

greater than 1.5 times the height of the box.

If a test score lies at the first quartile, it is A.higher than 25% of the scores. B.the same as the median. C.the same as the mode. D.higher than 75% of the scores.

higher than 25% of the scores.

A line chart is also known as a A.pie chart. B.line chart. C.bar chart. D.histogram.

histogram and bar chart

Which of the following survey items would generate a discrete variable? A.How old are you? B.How long does it take you to commute to work? C.How much did you pay in taxes last year? D.How many cars do you own right now?

how many cars do you own right now?

In time, the variable precedes the variable. A.hypothetical, theoretical B.discrete, continuous C.independent, dependent D.dependent, independent

independent, dependent

A survey administered to a sample drawn from a local community finds that a person's political party affiliation is related to whether or not they favor an increase in local sales tax (the headline of a newspaper story based on this poll reads: "Republicans support proposed tax increase"). This is an example of the use of A.univariate descriptive statistics. B.inferential statistics. C.multivariate descriptive statistics. D.reductionist statistics.

inferential statistics

Data is the same thing as A.information collected in numerical form. B.information collected in any form. C.statistics. D.proof.

information collected in numerical form.

Since computation of the standard deviation requires addition, division, and other mathematical operations, it should be used for A.interval-ratio level variables. B.non-continuous variables at any level of measurement. C.nominal level variables. D.discrete variables only.

interval-ratio level variables.

One problem with the range (R) as a measure of dispersion is that it A.is very difficult to calculate. B.ignores the most extreme scores. C.can be used only for nominal level variables. D.is based on only the most extreme scores.

is based on only the most extreme scores.

The graphical presentation method that uses midpoints rather than real limits is a A.pie chart. B.line chart. C.histogram. D.bar chart.

line chart

Which of the following is NOT a nominal level variable? A.Level of education B.Zip code C.Occupation D.Make of auto

lvl of education

In social research the purpose of statistics is to A.prove that the research theory is correct. B.validate the research project design. C.manipulate and analyze data. D.ensure acceptance by the scientific community.

manipulate and analyze data.

For variables measured at the interval-ratio level, the preferred measure of central tendency would be the A.mode. B.quartile. C.mean. D.decile.

mean

When interval-ratio data are badly skewed, the appropriate measure of central tendency is the A.mode B.median C.mean D.first quartile

mean

The central tendency measure that can be applied to nominal data is the A.median. B.mode. C.mean. D.you can use any measure on nominal data.

mode

The tails of the theoretical normal curve A.intersect with the horizontal axis between the 4th and 5th standard deviation. B.intersect with the horizontal axis beyond the 5th standard deviation. C.never touch the horizontal axis. D.maintain the same distance above the horizontal axis beyond the 3rd standard deviation.

never touch the horizontal axis.

The range (R) is found by subtracting the lowest from the highest score in the distribution. Therefore, R could NOT be found for A.nominal level variables. B.discrete variables. C.ordinal level variables. D.continuous variables.

nominal level variables.

On a test, the numbers used to identify the questions would be in level of measurement while the number of correct responses would be . A.nominal, interval-ratio B.interval-ratio, nominal C.continuous, discrete D.ordinal, nominal

nominal, interval-ratio

Select the variable(s) that can be measured at the interval-ratio level A.different types of crimes. B.number of children in a family. C.attractiveness of a person. D.emotional stability.

number of children in a family.

The median is the score of the middle case when the number of cases is A.odd. B.even. C.more than 20. D.less than 20.

odd

In the research process, the role of statistics is limited because A.numbers don't prove anything. B.of possible flaws in research design or method. C.the researcher may not be a mathematician. D.people lie when answering questionnaires.

of possible flaws in research design or method.

A Z score of +1.00 indicates a score that lies A.one standard deviation unit to the right of the mean. B.one standard deviation unit to the left of the mean. C.1/2 of one standard deviation unit on each side of the mean. D.Any of the above are possible.

one standard deviation unit to the right of the mean.

The variable socioeconomic status ranges from upper class to lower class and is an example of the A.nominal level of measurement. B.ordinal level of measurement. C.interval-ratio level of measurement. D.ratio level of measurement.

ordinal level of measurement.

Unlike empirical distribution, the theoretical normal curve is A.positively skewed. B.negatively skewed. C.bimodal. D.perfectly symmetrical.

perfectly symmetrical

For a single variable measured at the nominal level, an appropriate graph would be a A.pie chart. B.histogram. C.frequency polygon. D.bivariate table

pie chart

Proportions and percentages, ratios and rates are all ways of expressing A.concise distributions of a variable. B.data without leaving out any details. C.relative frequencies. D.raw frequencies.

relative frequencies

To compute a median for scores that have been grouped into a frequency distribution, we assume that the scores in each interval are A.spaced evenly across the interval. B.located at the upper real limit of the interval. C.located at the midpoint of the interval.

spaced evenly across the interval.

Converting scores into Z scores standardizes the original distribution to units of the A.median. B.standard deviation. C.mean. D.percentage.

standard deviation.

The expression Σ(Xi) directs us to find the A.average of the scores. B.middle score. C.sum of the scores. D.median.

sum of the scores.

In a ranked list of 25 scores, the median is the score of A.the 12th case. B.the 13th case. C.the average of the scores of the 12th and 13th cases. D.the average of all of the scores.

the 13th case.

The fourth decile would be at the same location as A.the second quartile. B.the fourth percentile. C.the fortieth percentile. D.the fourth quartile.

the fortieth percentile

In a campaign debate over the level of prosperity in the state, the incumbent governor says: "average income is A.the governor is citing the median. B.the opponent is using the mode. C.the opponent is using the mean. D.the governor is using the mean.

the governor is using the mean.

The greater the skew of a distribution of scores, A.the lower the value of the standard deviation. B.the higher the value of the standard deviation. C.the lower the value of the range. D.None of the above: measures of dispersion are not affected by skew.

the higher the value of the standard deviation

Which measure of central tendency is affected by every score in the distribution? A.The mean B.The median C.The mode D.All of the above

the mean

The second quartile (Q2) is equal in value to A.the mode. B.the median. C.the mean. D.the range.

the median.

A line chart or frequency polygon is based on A.the upper limits of each interval. B.the lower limits of each interval. C.the midpoint of each interval. D.any limit which the researcher selects.

the midpoint of each interval.

To calculate a proportion, the number of cases in any category (f) is divided by A.the total number of categories (k). B.the number of cases in all categories (N). C.the cases in that category (f). D.the number of cases in adjacent categories (k-1).

the number of cases in all categories (N).

You ask a sample of 27 students in a particular dorm on campus about their religious beliefs and use this information to make generalizations about all students in the dorm. In this research situation A.the 27 students questioned are a population. B.the dorm is a sample. C.this is an example of descriptive statistics. D.the sample is the 27 students who were questioned.

the sample is the 27 students who were questioned.

A defining characteristic of the normal curve is that it is A.theoretical. B.positively skewed. C.negatively skewed. D.perfectly nonsymmetrical.

theoretical.

If a distribution of scores has a mean of 30 and a range of 0 A.the variance is 30. B.the quartile deviation (Q) is 10. C.there is no dispersion in the distribution. D.the standard deviation is 1.

there is no dispersion in the distribution.

If the standard deviation of a group of scores is 0, A.the range would be at a maximum value. B.there is maximum variation in the scores. C.there is no variation in the scores. D.the mean is larger than the median.

there is no variation in the scores.

The problem with "push polls" is that A.they do not use the scientific method. B.they rely too much on scientific sampling. C.they rarely have hypotheses. D.they require very large samples.

they do not use the scientific method.?

The lower limit for the standard deviation is 0; the upper limit is A.the score of the mean. B.the score of the median. C.a function of the number of cases. D.undefined; there is no upper limit.

undefined; there is no upper limit.

The statement "Eight out of ten elderly residents fear victimization" is an example of A.inferential statistics. B.univariate descriptive statistics. C.multivariate descriptive statistics. D.inductive statistics.

univariate descriptive statistics.

The sum of the differences between the scores of a distribution and the mean of the scores is always A.0. B.1. C.the same as the number of cases. D.None of the above

0

The probability that a randomly selected case will have a score beyond ± 1.00 standard deviation of the mean is A.0.6826. B.0.5000. C.0.3174. D.1/2 of the area of 1 standard deviation.

0.3174

Which of the following data sets shows the greatest variability? A.9, 10, 11 B.0, 5, 9 C.50, 60, 170 D.31, 33, 35

50,60,170

The sum of the proportions for all categories of a variable will be A.10.00 B.1.00 C.0.10 D.100.00

1.00

In a distribution of 150 test scores, the mean grade was an 82 and the standard deviation was 8. If a student scored a 93, what would their equivalent Z score be? A.1.13 B.1.58 C.0.68 D.1.38

1.38

If the scores on a variable are 11, 14, 18, 20, and 25, the median is A.3 B.16 C.18 D.19

18

The class intervals below represent ages of respondents. Which set of intervals is both exhaustive and mutually exclusive? A.18-19 B.18-19 C.18-20 D.18-19

18-20

Forty of every two hundred students attend all of their classes. What percentage of the student body is this? A.5% B.50% C.2% D.20%

20%

For the following stated limits: 23-30 A.22-31 B.23-29 C.23.0-29.9 D.22.5-30.5

22.5-30.5

What is the mean of the following scores? 13 18 23 35 41

26

On January 1, 2013, a police department implemented tougher patrols for drunk driving. The number of drunk driving fatalities in the jurisdiction was 32 in 2012, and 23 in 2013. By what percentage did the new patrols reduce fatalities? A.25% B.28% C.39% D.42%

28%

The Z score table gives the area between a score and the mean. For a Z score of -1.00, that area (in percentages) is A.34.13% B.-34.13% C.68.26% D.-68.26%

34.13

Twenty-three of the 50 states rejected a proposed constitutional amendment to make the house fly the National Insect. What percentage is this? A.23% B.25% C.46% D.54%

46%

The area beyond ± 2 standard deviations contains approximately what % of the area under the normal curve? A.75% B.50% C.99% D.5%

5%

The homicide rate for a city is reported as 23.89. This means that A.for every homicide, there were 23.89 victims. B.For every 100,000 people in the population there were 23.89 homicides. C.The homicide rate is rising. D.There was an average of 23.89 homicides each month.

For every 100,000 people in the population there were 23.89 homicides.

Computation of a mean (or average) is completely justified when a variable is measured at which level? A.Interval-ratio B.Ordinal C.Nominal D.Discrete

Interval-ratio

A researcher has calculated the mean for a variable that is ordinal in level of measurement. A.This operation is a violation of level of measurement criterion and the results should be disregarded. B.This violation of level of measurement criterion is common and results should be treated with caution. C.No violation has occurred, this is a perfectly acceptable application of statistics. D.This is a mistake: means should never be calculated for ordinal variables because they are always continuous.

This violation of level of measurement criterion is common and results should be treated with caution.

Which of the following is a continuous variable? A.Number of children B.Time spent watching TV C.Number of times you have changed residences within the last five years D.Number of meals you consumed yesterday

Time spent watching TV

If people who eat at fast food restaurants become obese, obesity is

a dependent variable

If a distribution of test scores has a mean of 70 and a median of 80, the distribution has A.a few very high scores. B.a mode of 75. C.a negative skew. D.a positive skew.

a negative skew.