Test One

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The average number of children in a classroom is an example of a discrete variable.

False

E(X-X) equals

For any distribution of scores E(X-u)=

What is the value of 0.05 rounded to one decimal place?

0.1

What is the value of i?

Given the following set of numbers, X1 = 2, X2 = 4, X3 = 6, X4 = 10, what is the value of X4 squared?

100

Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the variance?

20.6

Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the value of E(x-x)2?

206

How many occurrences are there for the interval 60-69?

An industrial psychologist observed 8 drill-press operators for one working day. She recorded the number of times each operator pressed the "faster" button instead of the "stop" button to determine whether the design of the control panel was contributing to the high rate of accidents in the plant. The resulting scores were as follows: 5, 2, 8, 2, 3, 2, 4, 12 The median for this distribution is _________.

3.50

The lowest class interval is _________.

30-34

Given the data X1 = 1, X2 = 4, X3 = 5, X4 = 8, X5 = 10, evaluate N E i=2 (Xi+5).

Given the following set of numbers, X1 = 2, X2 = 4, X3 = 6, X4 = 10, what is the value of (∑X)/N?

5.5

The cumulative frequency for the interval 6.0-6.3 is _________.

5.7

Which of the following is (are) not a symmetrical distribution?

A J-shaped curve

The symbol "E" means:

Add the scores

If the scale upon which points A, B, C, and D are shown is an ordinal scale, we can meaningfully say _________.

C>B

What indicates the number of scores that fell below the upper real limit of each interval?

Cumulative frequency distribution

Number of bar presses is an example of a(n) _______ variable.

Discrete

A bell shaped curve is an example of a skewed distribution.

False

When constructing bar graphs, the bars do not touch each other because _______.

It emphasizes the lack of quantative relationship between the categories

Let's assume that we have determined the salary of all the professors at your school. In plotting the distribution of salaries we notice that it is positively skewed. For this distribution _________.

Mean> median

Which of the following is not a measure of central tendency?

Standard deviation

Interval or ratio data may be plotted as a _________.

b and c

Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the value of E(x-x)?

The relative frequency for the interval 76-85 is _________.

0.13

A history professor gives a quiz to his class and records the following scores: 13, 11, 11, 9, 12, 13, 16, 14, 11, 10, 8, 13, 20. The mode(s) for this distribution is(are) _________.

11 and 13

A history professor gives a quiz to his class and records the following scores: 13, 11, 11, 9, 12, 13, 16, 14, 11, 10, 8, 13, 20. The median for this distribution is _________.

A history professor gives a quiz to his class and records the following scores: 13, 11, 11, 9, 12, 13, 16, 14, 11, 10, 8, 13, 20. The range for this distribution is _________.

If s = 12 for a set of 200 scores and 5 points were subtracted from each of the scores, the new value of the standard deviation would be _________.

What is (4 - 2)(3×4)/(6/3)?

12.79

Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the mode?

Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the range?

How many occurrences fall below the upper real limit of the interval 70-79?

130

The mean weight for team A with 15 members is 140 lbs., the mean weight for team B with 7 members is 135 lbs., and the mean weight for team C with 20 members is 160 lbs. The overall mean weight for all three teams is _________.

148.69

Given the following set of numbers, X1 = 2, X2 = 4, X3 = 6, X4 = 10, what is the value of S X2?

156

Given the data X1 = 1, X2 = 4, X3 = 5, X4 = 8, X5 = 10, evaluate 4(E) i=2 Xi

Your new Mercedes weighs 1850 kilograms when measured to the nearest kilogram. The real limits of its weight are _________.

1849.5-1850.5

Which of the following numbers is rounded incorrectly to two decimal places?

21.47500= 21.47

Given the following set of numbers, X1 = 2, X2 = 4, X3 = 6, X4 = 10, what is the value for E X?

Given the data X1 = 1, X2 = 4, X3 = 5, X4 = 8, X5 = 10, evaluate S X (sigma x, sorry if S is being displayed rather than sigma).

The mean number of students in a classroom at school A is 32.5 and there are 25 classrooms. The mean number of students at school B is 29.6 in 12 classrooms. At school C the mean in each class is 15.3 for 10 classrooms. What is the mean number of students per classroom for all the schools combined?

28.1

Where 3X = 9, what is the value of X?

Given the data X1 = 1, X2 = 4, X3 = 5, X4 = 8, X5 = 10, evaluate N(E) i=2 Xi+5

The cumulative percentage for the interval 5.2-5.5 is _________.

36.11%

Given the following set of numbers, X1 = 2, X2 = 4, X3 = 6, X4 = 10, what is the value of N?

If the following scores were population scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What would the standard deviation be?

4.33

4.75

The real limits of the interval 56-65 are _________.

55.5-65.5

If the range of a distribution were 89 and the data were reported as whole numbers, what would the width of the class interval be if one chose to group the distribution into approximately 14 class intervals?

What are the real limits of the observation of 6.1 seconds (measured to the nearest second)?

6.05-6.15

The true limits of 7.0 are _________.

6.95-7.05

The range of a set of scores with a maximum value of 92 and a minimum value of 26 is _________.

If i = 7, the scores are integer, and the minimum value of the distribution of scores is 8, what would the lowest class interval be?

7-13

If the numbers in the left column are deciles, the median of the distribution falls in the range of _______.

70-79

Given the data X1 = 1, X2 = 4, X3 = 5, X4 = 8, X5 = 10, evaluate (E X)2.

784

The highest frequency for any interval is _________.

Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the mean?

8.0

In a certain statistics course, four exams were given. Each student's grade was based on a weighted average of his exam scores. The first two tests had weights of 1, the third test had a weight of 2, and the final test had a weight of 3. The exam scores for one student are listed below. The students overall average was __________.

86.44

Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the median?

A history professor gives a quiz to his class and records the following scores: 13, 11, 11, 9, 12, 13, 16, 14, 11, 10, 8, 13, 20. The variance for this distribution is _________. Assume sample scores.

9.76

The dependent variable in an experiment is defined or identified as _________.

A and C

A statistic is defined as __________.

A number calculated on sample data that quantifies a characteristic of the sample

In order to estimate the height of all students at your university, let's assume you have measured the height of all psychology majors at the university. If you had measured the height scores of all students at your university, these scores would constitute a

A parameter

In order to estimate the amount of TV watched by New York City adults, a sociologist surveys a random sample of adults from this city. All of the New York City adults constitute a ________

A population

In order to estimate the average (mean) weight of all professional football players, an investigator determines the weight of the "Dallas Cowboy" players. All professional football players constitute a _________.

A population

In order to estimate the average (mean) weight of all professional football players, an investigator determines the weight of the "Dallas Cowboy" players. The Dallas Cowboys are a _________.

A sample

In order to estimate the amount of TV watched by New York City adults, a sociologist surveys a random sample of adults from this city. The average (mean) of the raw scores is a _________.

A statistic

A variable is defined or identified as ____________.

A, C, and D

Descriptive statistics are used to _________.

All of these

Which of the following is not a measure of variability?

All of these are measures of variability

Which of the following is (are) not true?

All of these are true

If the scale upon which A, B, C, and D are arranged is an interval scale, we can say _________.

B-A=D-c

An accountant is preparing a graph showing the number of sports cars of various makers purchased this year. The number will be plotted on the ordinate and the various manufacturers on the abscissa. The proper type of graph for this data is a(n) _________.

Bar graph

E(X-X)2 equals

Cannot be determined from the information provided; E X2- (EX) 2/n and sum of squares

A nutritionist uses a scale that measures weight to the nearest 0.01 grams. A slice of cheese weighs 0.35 grams on the scale. The variable being measured is a _________.

Continuous variable

In order to estimate the amount of TV watched by New York City adults, a sociologist surveys a random sample of adults from this city. The obtained raw scores are called _________.

Data

In order to estimate the average (mean) weight of all professional football players, an investigator determines the weight of the "Dallas Cowboy" players. The weight of each Dallas Cowboy is(are) called ___________.

Data

Let's assume you are conducting an experiment to determine the effect of a new drug on the incidence of epileptic seizures. You select 20 epileptics from the 150 epileptics being treated at a nearby hospital and administer the drug to them. You record the number of seizures in each of the 20 subjects for one month. Then you record the number of seizures in each of the 20 subjects for one month without the drug. Being compulsive, you also record the number of seizures for the remaining 130 epileptics for one month. The number of seizures for each of the 130 epileptics constitutes _________.

Data

Considering again the information in problem 40, what would be the effect of adding those same new scores on the value of s?

Decrease s

In order to estimate the average (mean) weight of all professional football players, an investigator determines the weight of the "Dallas Cowboy" players. Weight is an example of a(n) ________

Dependent variable

On a physics exam, the instructor gives a bonus question worth 10 points. The class average (mean) without counting the bonus question is 83. If everyone gets the bonus question correct, the class mean would _________.

Equal 93

A deviation score is the same thing as a raw score.

False

A frequency distribution of grouped scores is used for distributions that have relatively few scores to stretch them out.

False

A histogram is like a bar graph except with a histogram the bars don't touch each other.

False

A relative frequency distribution indicates the total number of scores which occurred in each interval.

False

All frequency distributions should be of grouped scores.

False

All scales possess magnitude, equal intervals between adjacent units, and an absolute zero point.

False

An ordinal scale possesses the attributes of magnitude and equal interval.

False

By changing the value of one score in a sample this will necessarily cause the median to change.

False

By changing the value of one score in a sample this will necessarily cause the mode to change.

False

Central tendency and variability are synonymous.

False

Descriptive statistics are used to make inferences about the population.

False

E(X-X)2=0

False

For data that are not normally distributed, the standard deviation will sometimes be negative.

False

For the frequency distribution shown in the following table, N = 4.

False

For the frequency distribution shown in the following table, sigma X = 25.

False

If the distribution contains unbalanced extreme scores, the mean is a better descriptor than the median.

False

If the frequency of any score is zero, it should not be listed in a frequency distribution.

False

If the number of raw scores is odd, the median is always the score in the middle position.

False

If the remainder of a number = 1/2, we always round the last digit up.

False

In a cumulative percentage curve, percentage is shown on the abscissa.

False

In a skewed distribution, the mean and median are equal.

False

In constructing a frequency distribution of grouped scores, i should be rounded to one more decimal place than in the raw scores.

False

In general, E X2= (EX)2

False

In inferential statistics random sampling is regarded as desirable but not essential.

False

In inferential statistics random sampling is regarded as desirable, but not essential.

False

Intuition is not a valid way of developing research hypotheses.

False

It is legitimate to do ratios with interval scaling.

False

It is standard practice to carry all intermediate calculations to four more decimal places than will be reported in the final answer.

False

Measures of variability quantify the extent of dispersion in a set of scores.

False

Most scales used for measuring psychological variables are either ratio or interval.

False

Naturalistic observation is rarely used by scientists because it does not make use of the scientific method.

False

Nominal scales can be used either qualitatively or quantitatively.

False

Observational studies involve the manipulation of variables by the investigator.

False

One generally has to specify the real limits for discrete variables since they cannot be measured accurately.

False

Stem and leaf diagrams are like histograms, except that they lose the original scores.

False

The dependent variable is the variable that is systematically manipulated.

False

The equation for standard deviation is the same regardless of whether the scores are of a sample or a population.

False

The formula for the population standard deviation is square root of E(X-X)2/N-1

False

The independent variable is the variable that is measured to determine the effect of the dependent variable

False

The lower limit in the lowest class interval should equal i.

False

The mean must have a value equal to one of the scores in the distribution.

False

The median is less subject to sampling variation than the mean.

False

The median is most affected by unbalanced extreme scores.

False

The mode is used extensively in the behavioral sciences.

False

The number of students in a class is an example of a continuous variable.

False

The only value of random sampling is to achieve a representative sample.

False

The overall mean does not take into account the different number of subjects in each group.

False

The percentile point for a distribution of scores must have a value equal to one of the scores.

False

The real limits of a discrete variable are those values that are above and below the recorded value by one half of the smallest measuring unit of the scale.

False

The symbol S means square the following numbers and sum them.

False

The variance is the square root of the standard deviation.

False

When constructing frequency distributions there must be 12 class intervals.

False

When constructing the frequency distribution it is customary to show the real limits of the class intervals in the table.

False

When rounding, if the decimal remainder is equal to 1/2 and the last digit of the answer is even, add 1 to the last digit of the answer.

False

With nominal scales there is a numerical relationship between the units of the scale.

False

With the exception of division, one can perform all mathematical operations on a ratio scale.

False

The variable that the experimenter manipulates is called the _________.

Independent variable

Mathematical methods used to draw tentative conclusions about a population based on sample data are referred to as _________.

Inferential statistics

In a negatively skewed distribution, the mean will generally be _______ the median.

Less than

If the distribution is symmetrical, which is the best measure of central tendency?

Mean

The most commonly encountered measure of central tendency is the _________.

Mean

Consider the following scores: 21, 22, 22, 0.1, 20, 25, 28, 26, 23, 19, 0.5. Which of the measures listed below would give the best description of the central tendency of these scores?

Median

In a bell-shaped distribution, _________.

Median = mean

Which method of knowing is used in the following example? An individual accepts as true that there is an afterlife because a minister asserts such is the case.

Method of Authority

The mean is _______ sensitive to extreme scores than the median.

A curve is negatively skewed when _________.

Most of the scores occur at the higher end of the horizontal axis and the curve tails off toward the lower end

In calculating the standard deviation of a sample, we use _________ in the denominator.

N-1

A distribution has a mean of 78 and a median of 92. This distribution is _________.

Negatively skewed

This score distribution is _______.

Negatively skewed

If the scale upon which A, B, C, and D are arranged is a nominal scale, we can say _________.

Neither a nor b

A continuous scale of measurement is different than a discrete scale in that a continuous scale _________.

Never provides exact measurements and can take an infinite number of intermediate possible values

An individual is measuring various objects. If the measurements made are to determine into which of six categories each object belongs, the measuring scale used must have been a(an)_______ scale.

Nominal

Classifying subjects on the basis of sex is an example of using what kind of scale?

Nominal

Sex of children is an example of a(n) _________ scale.

Nominal

"Brand of soft drink" is measured on a(n) _________.

Nominal scale

In a 10-mile cross-country race, all runners are randomly assigned an identification number. These numbers represent a(n) _________.

Nominal scale

At the annual sailing regatta, prizes are awarded for 1st, 2nd, 3rd, 4th, and 5th place. These "places" comprise a(n) _________.

Ordinal scale

In order to estimate the average (mean) weight of all professional football players, an investigator determines the weight of the "Dallas Cowboy" players. The average (mean) weight of all professional football players is called a _________.

Parameter

In order to estimate the height of all students at your university, let's assume you have measured the height of all psychology majors at the university, the average (mean) of these scores would constitute a ____________.

Parameter

A distribution which has a predominance of scores at the lower values of the distribution and which tails off at the higher end is _______.

Positively skewed

If a large psychology class took a test on theoretical biophysics, the distribution of scores would probably be _________.

Positively skewed

Which of the following do (does) not measure average dispersion?

Range and sum of squares

The number of legs on a centipede is an example of a(an) _______ scale.

Ratio

In the race mentioned in question 26, a comparison of each runner's finishing time would represent a(n) _________.

Ratio scale

Reaction time in seconds is an example of a(n) _________ scale.

Ratios

What indicates the proportion of the total number of scores that occurred in each interval?

Relative frequency distribution

If a constant of 5 is subtracted from all of the scores, the standard deviation _________.

Remains the same

In order to estimate the height of all students at your university, let's assume you have measured the height of all psychology majors at the university. The psychology majors constitute a _________.

Sample

In order to estimate the ratio of white to black students in his college, a professor determines the proportion of whites and blacks in his class. The students in the professor's class are called a _________.

Sample

In inferential statistics the object is usually to generalize from a _________ to a _________.

Sample; population

In acquiring knowledge the method that employs logic, reasoning and objective assessment is referred to as _______.

Scientific method

Which of the following variables has been labeled with an incorrect measuring scale?

Self-rating of anxiety level by students in a statistics class- ratio

Statistic

In order to estimate the ratio of white to black students in his college, a professor determines the proportion of whites and blacks in his class. The resulting proportion is called a _________.

Statistic

When one analyzes data based on a sample, one calculates a _________.

Statistic

This score diagram is called a _________.

Stem and leaf diagram

Descriptive statistics are helpful in _________ and _________ raw data.

Summarizing; characterizing

What is the appropriate symbol for the population standard deviation?

The answer is the third option

In a frequency polygon the points are plotted over _______ at a height corresponding to the frequency of the interval.

The midpoint of each interval

If 10 points were added to each score in a distribution, which of the following will happen?

The standard deviation will be unchanged

If 5 points are added to each score in a distribution, which of the following will happen?

The standard deviation will be unchanged

A percentile point is defined as _________.

The value on the measurement scale below which a specified percentage of the scores fall

Consider a distribution with N = 100, X = 50, and E(X-X)2 = 9875. If 10 new scores of 50 were added to the distribution, what would happen to the sum of squares?

The value would remain unchanged

A "U" shaped distribution is an example of a symmetrical distribution.

True

A discrete variable requires nominal or interval scaling.

True

A frequency distribution presents the score values and their frequency of occurrence.

True

A frequency polygon results in a curve that looks as though the scores were continuously distributed.

True

A fundamental property of a nominal scale is equivalence.

True

A statistic is to a sample as a parameter is to a population.

True

By changing the value of one score in a sample this will necessarily cause the mean to change.

True

Central tendency describes the central location of the set of scores.

True

Data are an indispensable part of scientific method.

True

Determining the number of students in each section of introductory psychology involves the use of a ratio scale.

True

E(X-X)=0

True

If IQ was measured on a ratio scale, and John had an IQ of 40 and Fred an IQ of 80, it would be correct to say that Fred was twice as intelligent as John.

True

If a curve is negatively skewed, most of the scores occur at the higher values and the curve tails off toward the lower end of the horizontal axis.

True

If a group of 100 people has an average IQ of 107 and a group of 50 people has an average IQ of 101, the average IQ of all the people is 105.

True

If one knows S X, N, and S X2, one can calculate both the variance and the standard deviation. It is not necessary to know the mean itself.

True

If one measured the height of all the women at a university and took an average of the data, the university women would be a sample of the population of all university women in the world.

True

If the quantity S X = 400.3 for N observations, then the quantity S X will equal 40.03 if each of the original observations is multiplied by 0.1.

True

In a positively skewed distribution, the mean has a higher value than the median.

True

In a race, Sam came in first and Fred second. Determining the difference in time to complete the race between Sam and Fred involves an ordinal scale

True

In an experiment conducted to determine the effect of testosterone on aggression, testosterone is the independent variable.

True

In constructing a frequency distribution of grouped scores, the intervals must be continuous and mutually exclusive.

True

In grouping scores, the wider the intervals, the more information that is lost.

True

In order to determine cause and effect, a researcher needs to do a true experiment.

True

In order to determine the cause and effect, a researcher needs to do a true experiment.

True

In rounding, if the remainder beyond the last digit is greater than 1/2, add one to the last digit. If the remainder is less than 1/2, leave the last digit as it is.

True

It is possible to have a set of scores with three different values for central tendency.

True

It is possible to have more than one mode in a sample of scores.

True

One reason for constructing frequency distributions is to be able to visualize the shape of the distribution.

True

The equation for the sum of squares of a sample is SS=EX2/N

True

The main difference between rationalism and the scientific method is that the scientific method relies on objective assessment to test the idea

True

The mean is more often used for inference than the median.

True

The mean is the arithmetic average of the scores.

True

The mean is the most sensitive measure of central tendency to extreme scores.

True

The mean is the same as the arithmetic average.

True

The median and the 50th percentile rank score will always have the same value.

True

The method of authority is opposed to the scientific method.

True

The overall mean is a weighted mean.

True

The percentile rank of a score is equal to the percentage of scores in the distribution that fall below the score in question.

True

The range is equal to the highest score minus the lowest score.

True

The variance is the square of the standard deviation.

True

To determine the width of the class interval, i, divide the range by the number of class intervals.

True

We use N - 1 in the denominator of the equation for calculating the sample standard deviation because it provides us with an accurate estimate of the population standard deviation.

True

When data has not yet been analyzed, this is called raw data.

True

When doing summation, the number above the summation sign indicates the term ending the summation and the number below indicates the beginning term.

True

With an ordinal scale one cannot be certain that the magnitude of the distance between any two adjacent points is the same.

True

With grouped scores, the mode is the mid-point of the interval with the highest frequency.

True

Assume one has a set of 35 scores with X=100 and s=9. If 5 scores , each equal to 100 were added to the distribution, what effect would this have on X?

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