Test One
The average number of children in a classroom is an example of a discrete variable.
False
E(X-X) equals
0
For any distribution of scores E(X-u)=
0
What is the value of 0.05 rounded to one decimal place?
0.1
What is the value of i?
10
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?
21
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).
47
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)?
0
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 _________.
12
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 _________.
12
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 _________.
12
What is (4 - 2)(3×4)/(6/3)?
12
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 variance for this distribution is _________. Assume sample data.
12.79
Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the mode?
13
Given the following set of scores X: 10, 12, 6, 8, 9, 11, 13, 13, 5, 0, 1 What is the range?
13
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
17
Your new Mercedes weighs 1850 kilograms when measured to the nearest kilogram. The real limits of its weight are _________.
1849.5-1850.5
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 mode for this distribution is _________.
2
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?
22
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).
28
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?
3
Given the data X1 = 1, X2 = 4, X3 = 5, X4 = 8, X5 = 10, evaluate N(E) i=2 Xi+5
32
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?
4
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
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 mean for this distribution is _________.
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?
6
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 _________.
66
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 _________.
8
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?
9
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
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. The 150 epileptics constitute _________.
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
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. The average (mean) number of seizures for the 20 subjects is called _________
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. The number of seizures for each of the 20 subjects constitutes _________.
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
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. Incidence of seizures 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.
More
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
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 the Dallas Cowboys is called a _________.
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?
X would remain unchanged
X6/X2 equals _______
X4
X = Y/Z can be expressed as _______
Y=(Z)(X)
For X + Y = Z, X equals _______.
Z-Y
The purpose of a frequency distribution is to _________.
a and b