Harding, Psych stats 325, chapters 4-6
A cognitive psychologist found that the mean recall of information increased as a function of the extent to which the participants elaboration the material (none, minimal, extensive). Also, the standara deviation for each condition was small. What does this suggest about the relationship between the amount of elaboration and recall? A. A strong relationship exist B. A weak relationship exist C. No relationship exists D. A moderate relationship exists
A
A score's deviation conveys two pieces of information about the score's location: the number indicates _____, and the sign indicates _____. A. The score's distance from the mean; whether the score is greater or less than the mean. B. whether the score is greater or less than the mean; the score's distance from the mean. C. The size of the score; whether the score is a good score. D. whether the score is a good score; whether the score is positive or negative.
A
Find the median of the following data set. 8,7,2,4,4,8,2,4,6,5,7,3,9,4,5,4,7 A. 5 B. 4 C. 5.24 D. 7
A
Five students took a personality test. Their deviation scores were -4 +3 +1 -2 +2. Assuming that these scores form a normal distribution, which of the following orders represents their ranking in terms if frequency, from highest to lowest? A. +1, +2 and -2, +3, -4 B. -4, +3, +2 and -2, +1 C. -4, -2, +1, +2, +3 D. +3, +2, +1, -2, -4
A
Multiplying each of the scores in a distribution by a constant a. multiplies the standard deviation by the same constant b. multiplies the standard deviation by half the amount of the constant c. multiplies the standard deviation by 34% of the constant d. does not change the value of the standard deviation
A
Of the three kinds of variances, which use(s) N-1 in the final division? a. The estimated population variance (s²x) b. the sample variance (S²x) c. the population variance (σ²x) d. All three
A
The distribution of weights of men in the American population is not symmetrical. Most weights are bunched together at the lower end of the distribution. As weights increase, there are fewer and fewer men with these weights. how would you describe the relationship between the mean, the median, and the mode in this distribution? A. mode < median < mean B. mean < median < mode C. mean = median = mode D. median < mode < mean
A
The mean is used most often in behavioral research because researchers tend to... A. Measure variables that have interval or ratio scores, and the scores form approximately normal distributions. B. conduct research in which the mathematical center of a distribution is required. C. conduct research in which only the most frequently occurring score is needed. D. Measure variables that have interval or ratio scores, and the scores usually do not form a normal distribution.
A
The mode is defined as... A. the most frequently occurring score. B. the mathematical center of the distribution. C. the smallest deviation from the mean. D. the point at or below which 50% of the scores fall.
A
The mode is the appropriate measure of central tendency when the scale of measurement is.... A. nominal. B. ordinal. C. interval. D. ratio.
A
Using the appropriate values from the z-table in the textbook appendix, find the z-score for which the area beyond z in the tail is .2546. a. .66 b. .2454 c. -.66 d. -.2454
A
What happens to the mean of a distribution if every score is divided by 10? A. its value is divided by 10. B. its value is multiplied by 10. C. its value is decreased by 10 points. D. its value is increased by 10 points.
A
When all the scores in a set of data are the same, what is S²x? A 0 B Greater than 0 C Less than 0 D Unknown; cannot compute without the scores
A
When the standard deviation of a raw score distribution is large, the corresponding z-score distribution will be a. relatively spread out b. relatively narrow c. positively skewed d. negatively skewed
A
When two normal z-distributions are plotted on the same graph, what can we say about the relative frequency of each z-score? a. It will always be the same b. It will always be different C. It depends on the raw score mean d. It depends on the raw score standard deviation
A
When we graph results from an Experiment, a line graph is appropriate when... A. The independent variable is interval or ratio B. The independent variable is nominal or ordinal C. The dependent variable is nominal or ordinal. D. The dependent variable is interval or ratio
A
When we graph the results of an experiment, the Y axis indicates the... A. measure of central tendency we have used for the dependent variable. B. Raw score values for each subject on the dependent variable. C. Raw scores for each of the independent variable. D. Levels of the independent variable.
A
Which of the following is NOT communicated by a measure of variability? A. the location of the distribution b. how consistently close to the mean the scores are c. how spread out the distribution is d. the differences among the scores
A
Why is the median unaffected by extreme scores occurring in only one tail of the distribution. A. because the median does not take into account the actual values of all the scores. B. because the median takes into account the actual values of all the scores. C. because the median is only one point in the while distribution. D. because the median is based on how frequently the median score occurs.
A
With respect to a graph of a frequency distribution, a positive deviation score... A. will be located to the right of the mean. B. will be located to the left of the mean. C. cannot be found. D. indicated the raw score's location relative to the median.
A
Your sense of direction puts you at the 39th percentile, relative to a raw score distribution with a mean of 3.5 and a standard deviation of 1. What is your z-score? a. -.28 b. +.28 c. +1.23 D. -1.23
A
A program evaluator for a large school district wants to know how much intelligence varies in the elementary schools. She randomly selects one classroom at each grade level in each elementary school and administers an intelligence test to the children in those classrooms. In order to find out which school has the most consistent intelligence level, which of the following should she calculate for each school? A. The mean b. The standard deviation c. The median D. The Range
B
A researcher found that the relationship between map-reading ability and way-finding ability accounts for a .15 of the total variance in way-finding ability. This means that a. the relationship between map-reading ability and way-finding ability is strong because the variability is so low b. the relationship between map-reading ability and way-finding ability is weak because only 15% of the variance is accounted for c. there is no way to speculate about the relationship based on this information d. this researcher should recheck all calculations because this value is not possible
B
Alicia scored a 70 on her psychology quiz, but the class as a whole averaged a 40. If the standard deviation was 10 what was alicia's z-score? a. -3 b. +3 c. -.3 d +.3
B
As the N of the samples used in a sampling distribution _______, the sampling distribution becomes ______. a. decreases; more like a perfect normal curve b. increases; more like a perfect normal curve c. decreases; less spread out d. increases; more spread out
B
Find the mode of the following data set: 8,7,2,4,4,8,2,4,6,5,7,3,9,4,5,4,7 A. 5. B. 4. C. 5.24. D 7
B
Five students took a personality test. Their deviation scores were -4 +3 +1 -2 +2. Assuming that these scores form a normal distribution, which deviation represents the highest raw score? A. -4 B. +3 C. +2 D. +1
B
For the following set of scores, what is (are) (x - x̄)? 7,8,10,10,11,12,13,13,15 A. 4,3,2,1,0,-1,-2,-2,-4 B. -4,-3,-1,-1,0,1,2,2,3, C. 4,3,1,1,0,1,2,2,4 D. 0
B
For the following set of scores, what is the z-score for a raw score of 23? 22,23,19,25,26,22,19,25,22,20,21,23,23,24,18,20, 22,24,21,21,20,24,22,21,23 a. 1.25 b. .50 c. .34 d. .68
B
Given a normal distribution, as z-scores' absolute values increase, those z-scores and the raw scores that correspond to them occur a. more frequently b. less frequently c. more frequently at first and then less frequently d. less frequently at first and then more frequently
B
Given any z-score, it is safe to say that the absolute value is a good indicator of ____________ and the sign (+ or -) is a good indicator of ___________. A. direction; distance b. distance; direction c. frequency; amount d. amount; frequency
B
Graphs in book (Chapter 4 #61)
B
Graphs in book (Chapter 4. #32) LOOK AT THEM BEFORE ANSWER
B
If we add 1Sx to x̄ and subtract 1Sx from x̄, the interval we have created a. encompasses approximately 34% of the scores in the sample b. encompasses approximately 68% of the scores in the sample c. is approximately 68% of the range d. is approximately 68% of the semi-interquartile range
B
If we are going to predict future performance on the basis of a sample mean and sample standard deviation, it is desirable to have a a. small mean b. small standard deviation c. large mean d. large standard deviation
B
In a graph of the relationship between the level of nose in a environment and the number of errors a person makes, the ____ is on the X axis and the ____ is on the Y axis. A. Number of errors; frequency of errors B. level of noise; number of errors C. level of noise; frequency of noise D. number of errors; level of noise
B
In roughly normal distributions, the standard deviation is approximately a. Equivalent to the variance b. one-sixth of the range c. equivalent to the deviation of the median from the brain d.one fifth of the absolute value of the mean
B
In sampling distributions, all the samples contain sets of raw scores a. with the same variance b. from the same population c. with the same mean d. that are representative of the population mean
B
In which of the following sets of data would the mode be inappropriate? A. 3,4,5,5,5,6,7 B. 3,4,5,6,7 C. 3,4,4,4,5,5,6,7 D. 3,4,5,5,6,7
B
Measures of central tendency are measures of... A. Distance. B. Location. C. Deviation. D. Extremes.
B
On a recent paper, Maria's score, transformed to a z-score, was a +1. If the cutoff mark is the upper 10% of the class for As, the upper 10% to 20% for B's, the upper 20% to 30% for C's, and the upper 30% to 40% for D's (below 60% being a failure), what grade did maria receive on the quiz? A. A B. B C. C D. F
B
On any graph a horizontal line of data points indicates that... A. the Y scores are changing as the X scores change, and there is a relationship present. B. The Y score are not changing as the X scores change, and there is no relationship present. C. the independent and dependent variables have been placed on the wrong axes and should be reversed. D. every score is occurring with a different frequency
B
One way to measure the ability to find one's way in an environment is to ask people to rate themselves on a sense of direction scale. The scale ranges from 1 (poor) to 7 (good). In a sample of college students, including yourself, the mean rating of sense of direction is 3, with a standard deviation of 1. If you gave yourself a rating of 2, what is your z-score? A. .57 B. -1.0 C. +1.5 D. 2.0
B
Standard deviation is defined as the square root of the a. average of the deviations around the mean b. average of the squared deviations around the mean c. sum of the deviations around the mean d. sum of the squared deviations around the mean
B
Sx and S²x are considered biased estimates for the population standard deviation and variance because, over many calculations, they tend to be a. overestimates b. underestimates c. inaccurate in an unpredictable way d. accurate estimates
B
S²x is the symbol for a. population variance b. sample variance c. population standard deviation d. sample standard deviation
B
The mean of the sampling distribution always equals a. the mean of the sample, when the sample N is large b. the mean of the underlying raw score population c. 0 d 1
B
The median is the preferred measure of central tendency when... A. the scale of measurement is nominal. B. the scale of measurement is ordinal. C. the scale of measurement is ratio. D. the distribution is symmetrical and the scale of measurement is interval or ratio.
B
The population mean is estimated by... A. calculation the mean of as many scores as we can get from the population. B. calculation the mean of a random sample drawn from the population. C. calculating the mean of a random sample drawn from the population. D. calculating all measures of central tendency for a random sample from the population.
B
The red Cross wanted to know whether an ad campaign designed to persuade people to donate blood actually increased blood donations. For a sample of N=4 blood donation centers, the mean increase in blood donations was 10 pints, with a standard deviation of 2 pints. If the red cross could collect data from the entire population of blood donation centers, what would one expect the population standard deviation to be? a. 2 b. 2.31 c. 2.67 d. 20
B
The relative frequency(ies) obtained from the standard normal curve is (are) the __________ of the raw scores in our data, if the data formed a perfect normal distribution. a. z-scores b. expected relative frequency c. expected simple frequency d. model
B
The sample mean for a recent introductory psychology test was 78, and the sample variance was 9. If a student received a score of 82, what was this student's z-score? a. .44 b. 1.33 c. -1.33 d. -.44
B
The variance and standard deviation indicate how much the scores are spread out around a. the range b. the mean c. the median d. the mean
B
To evaluate a person for possible brain damage, a neuropsychologist gives the person a visual memory test and a reading test. To compare the person's performance across these two tests, what should the neuropsychologist do? A. Graph the raw score distribution for each test on the same graph B. Calculate a z-score for each test C. calculate z-scores for the sample means D. Find the simple frequency of the person's raw score for each test
B
Unbiased estimators sx and s²x of the population parameters will produce values that are _______ those produced by the biased estimators Sx and S²x. a. smaller than b. larger than c. the same as d. sometimes larger than and sometimes smaller than
B
Using the appropriate values from the z-table in the textbook appendix, find the area above (beyond) z=+.89 a. .3133 b. .1867 c. -.3133 d. -.1867
B
Variance is defined as A. Average of the deviations around the mean B. Average of the squared deviations around the mean C. Sum of the deviations around the mean, squared D. sum of the squared deviations around the mean
B
What is the range of the following data? 15,9,17,12,15,19,18,15,16,10,13 a. 5 b. 10 c. 14.45 d. 15
B
What raw score is at the 16th percentile (15.87 to be exact) when the mean of the distribution is 50 and the standard deviation is 4? a. 54 b. 46 c. 34 d. There is insufficient information to determine an answer
B
What were the sample means that marked the middle 68% in the state if the population mean was 500 and the standard deviation (standard error) for the sampling distribution was 200? a. 350 and 650 b. 300 and 700 c. 400 and 600 d. 450 and 550
B
When a distribution's mode > median > mean, it is said to be... A. positively skewed. B. negatively skewed C. symmetrical D. bimodal.
B
When it is impossible to obtain all the scores in a depopulation, the best estimate of the population mean is the... A. population median. B. sample mean. C. sample mode. D. sample median.
B
When the mean is used to predict scores, a deviation (x - x̄) indicates... A. the sample is representative of the population. B. the difference between the x̄ we predict and the score an individual actually gets. C. the sum of all the deviations. D. the individual's observed score.
B
When we refer to a score's deviation, we are referring to... A. how far it is from other scores. B. how far it is from the mean. C. how close it is to the other scores. D. how much error occurred in measuring it.
B
Which measure of central tendency is appropriate if the shape of the distribution is severely skewed. A. the mode. B. the median. C. the mean. D. the deviation.
B
Which measure of central tendency should be an academic counselor use to describe a students rank order in his/her classes? A. the mean. B. the Median C. the mode D. the deviation
B
Why shouldn't the mode be used with the following set of scores? 2,5,3,3,4,2,4,5,1,1 A. the data are obviously not nominal. B. there is no mode. C. the score are positively skewed. D. the scores are negatively skewed.
B
With respect to other scores in a distribution, measures of central tendency... A. are all around the other scores. B. are the points around which most of the scores are located. C. usually fall in the tails or extremes of the distribution. D. are never actually equal to one of those scores in the distribution.
B
Z-scores can be calculated from a. any data b. interval or ratio scores c. nominal or ordinal scores d. the range
B
Z-scores communicate a score's a. absolute magnitude b. relative location in a distribution c. distance from the population mean d. variability
B
the mean is defined as... A. the most frequently occurring score. B. the mathematical center of the distribution. C. the smallest deviation from the center score. D. the point at or below which 50% of the scores fall.
B
A group of 10 students participated in a study of nutritional awareness. what is the sample variance (S²x) of their scores? 20,19,22,20,15,18,15,21,19,20 A. 2.21 B. 2.33 C 4.89 D 5.43
C
A researcher has conducted an experiment in which the independent variable is room temperature. Two conditions (a hot room and a cold room) were used. The dependent variable was the length of time required to complete a jigsaw puzzle. What is the best way to state the there is a relationship? A. The mean times to complete the puzzle are not different fro the two room conditions. B. The mean room temperatures are not different for the length of time required to complete the jigsaw puzzle. C. The mean times complete the puzzle are different for the two room conditions. D.The mean room temperatures are different for the length of time required to complete the jigsaw puzzle.
C
A theoretically perfect normal curve, which serves as a model of the perfect normal z-distribution is called the a. sampling distribution of means b. standard, normalized z-distribution c. standard normal curve d. standard mean score distribution
C
Adding numbers is an important procedure in statistics. Instead of saying "add up all of these scores" we use the symbol... A. K. B. X. C. Σ. D. Y.
C
An experimenter investigated the ability to concentrate as a function of crowding. Concentration was measured as the amount of time it took the participant to complete a word puzzle. How should the experimenter summarize the scores on the dependent variable? A. Find the mode for crowding because crowding scores are nominal. B. Find the mean amount of crowding if the crowding scores are normally distributed. C. Find the mean amount of time it took to solve the puzzle, if time scores are normally distributed. D. Find the median amount of time it took to solve the puzzle because time scores are ordinal.
C
An experimenter investigated the ability to concentrate as a function of eye color. Eye color was classified as having either, brown eye, or other eye color. which type of graph should the experimenter use to display the results? A. X and Y B. Histogram C. Bar D. Line
C
Find the mean of the following data set. 8,7,2,4,4,8,2,4,6,5,7,3,9,4,5,4,7 A. 5 B. 4 C. 5.24 D. 7
C
Find the mean of the scores in the following frequency distribution. (S=Score) S | f 9 | 2 8 | 4 7 | 8 6 | 6 5 | 4 4 | 3 3 | 2 A. 8 B. 7 C. 6.21 D. 6
C
Find the mode of the scores in the following frequency distribution. (S=Score) S | f 9 | 2 8 | 4 7 | 8 6 | 6 5 | 4 4 | 3 3 | 2 A. 8 B. 6 C. 7 D. 6.21
C
For a distribution with x̄=50 and Sx=5, find the z-scores for each of the following raw scores: 50;65;45;42 a. 0;-3;1;1.6 b. 0; 6.71; -2.24; -3.58 c. 0; 3; -1; -1.6 d. 0; -6.71; 2.24; 3.58
C
If a class's scores are normally distributed, with a mean of 70 and a standard deviation of 10, what are the upper and lower limits of the middle 68% of the class? A. 50 and 90 B. 40 and 100 C. 60 and 80 D. 32 and 68
C
If raw scores ranging from 1-50 represented all the corresponding negative z-scores on the distribution, and raw scores ranging from 50 to 100 represented all the corresponding positive z-scores, what would be the total relative frequency of 50 to 100? A. 1.00 B. .75 C. .5 D. .25
C
If the variance for a sample is computed and it is found to be rather large, the numbers a. are tightly packed around the mode b. are tightly packed around the mean c. are spread out around the mean d. in the sample are close to one another
C
If there were 500 students in Jamal's class, approximately how many actual students scored higher than Jamal on the quiz if Jamal had a z-score of -2? a. 250 b. 340 c. 420 d. 490
C
In a skewed distribution the mathematical center is... A. the median, which is the point around which most of the scores tend to be located. B. the mode, which is the point around which most of the scores tend to be located. C. the mean, which is not the point around which most of the scores tend to be located. D. impossible to determine.
C
In a z-distribution, the standard deviation will always be a. greater than 1 b. less than 1 c. equal to 1 d. equal to 0
C
Pat's last statistics test score was 72. If the instructor tells Pat that the grade distribution was approximately normal, the class mean was 67, and the standard deviation was 3, which of the following is correct? a. A score of 72 is never good. B. Pat should be worried about this score, because many other students did better c. Pat should be fairly happy about this score, because many students did not do as well d. Pay should be ecstatic, because this is obviously one of the highest grades in the class
C
Suppose we compute Sx and find that it is equal to 5.5. How do we interpret this number? A. The numbers in the sample deviate, on the average, 5.5 units from one another. B. The numbers in the sample deviate, on the average 5.5 units from the two extreme scores c. The numbers in the same deviate on the average 5.5 units from the mean d. The numbers in the sample deviate no more than 2.25 units from the mean
C
The average of the deviations, Σ(x-x̄)/N, can never actually be computed. Why? A. you cannot subtract the mean from every number in the sample b.When you subtract the mean from some numbers, you get negative numbers. C. The sum of all deviations from the mean always equals zero D. The actual N is never truly known
C
The average score on the statistics quiz was a 70, and there was a standard deviation of 10 points. If Enrique had a z-score of -1.0, his raw score would be _______ and his percentile rank would be _______. a. 40; 2% b. 50; 16% c. 60; 16% d. 60; 34%
C
The best predictor of an individual score in a sample of scores is the... A. Sum of the deviations of the scores from the mean. B. score minus the mean. C. mean of the sample of scores. D. total error in the sample of scores.
C
The distribution of z-scores is always a. positively skewed b. negatively skewed c. the same as the distribution of raw scores d. more spread out than the distribution of raw scores
C
The equipment failed to record the reaction time for one trial in an experiment. The reaction times (in milliseconds)) for the other trials were 505, 630, 490, 650, and 560. What is the best guess for the missing value? A. 490.00 B. 560. C. 567.00 D. 568.75
C
The mean is inappropriate measure of central tendency when the distribution is severely skewed because... A. it is not the mathematical center of a skewed distribution. B. only 50% of the scores in a skewed distribution are near it. C. it does not accurately describe a skewed distribution. D. only the mode describes a skewed distribution.
C
The mean of the sampling distribution of means is always a. greater than the population mean b. less than the population mean c. equal to the population mean d. the population mean divided by the square root of N
C
The sample mean for a recent introductory psychology test was 78, and the sample variance was 9. If a student's z-score=-2.0, what was this student's raw test score? a. 84 b. 60 c. 72 d. 96
C
The variance can never be a. greater than the standard deviation b. zero c. a negative number d. greater than the mean
C
We can use the standard normal curve as our model for a. perfectly normal distributions only b perfectly normal distributions only, when transformed to z-scores c. any approximately normal distribution, when transformed to z-scores. d. any approximately normal distribution when transformed to percentiles
C
What do (S²x), (s²x), (σ²x) have in common? a. all are forms of standardized variance b. all are forms of standard deviation c. all are forms of variance d. all represent the location of a set of scores
C
When a distributions mode = median = mean, it is said to be... A. positively skewed. B. negatively skewed. C. symmetrical. D. bimodal.
C
When deciding which type of graph (bar, line, histogram, etc.) is appropriate, we consider the characteristics of the... A. Variability of the distribution B. Mean. C. Independent variable. D. Dependent variable.
C
When using the mean to predict scores, error is represented by.... A. the deviation of the median from the mean. B. a statistic obtained from a nonrandom sample. C. the deviation of a score from the mean. D. the differences between raw scores in a sample.
C
Which measure of central tendency is appropriate if the shape of the distribution is symmetrical and the measurement scale is interval or ratio? A. the mode B. the median C. the mean. D. the Deviation
C
Which measure of central tendency should a researcher use to describe the sex of participants in a study? A. the mean. B. the median. C. the mode. D. the deviation.
C
Your sense of direction puts you at the 79th percentile, relative to a raw score distribution with a mean of 3.5 and a standard deviation of 1. What is your z-score? a. +.13 B. +.5 C. +.81 D. -.81
C
μ is the symbol for the... A. population median. B. population mode. C. population mean. D. sample mean.
C
(S²x) is used to describe ___________, (s²x) describes ____________, (σ²x) describes _________ a. the estimate of the population variance; the population variance; the sample variance b. the sample variance; the population variance; the population variance c. the sample variance; the sample variance; the population variance d. the sample variance; the estimate of the population variance; the population variance
D
A deviation score is more informative than a raw score because it... A. describes the shape of the distribution. B. has a greater numeric value. C.. is a transformation of the raw score. D. gives the score's location relative to the mean.
D
A deviation score of -3 indicates that the raw score is... A. Greater than the mean. B. greater than the median. C. equal to the mean. D. Less than the mean.
D
A group of 10 students participated in a study of nutritional awareness. What is the estimated population standard deviation (sx)? 20,19,22,20,15,18,15,21,19,20 a. 5.43 b, 2.21 c. 4.89 d. 2.33
D
A program evaluator for a large school distinct wants to know how much intelligence varies in the elementary schools. She randomly selects one classroom at each grade level in each elementary school and administers and intelligence test to the children in those classrooms. If the program evaluator wants to predict how well a new student will fare in one of the elementary schools, she should a. calculate the mean and standard deviation for school performance b. calculate the variance and standard deviation for the intelligence scores c. calculate the range and the median for both intelligence and school performance d. find out if there is a relationship between intelligence level and elementary school performance
D
A program evaluator for a large school district wants to know how much intelligence varies in the elementary schools. She randomly selects one classroom at each grade level in each elementary school and administers an intelligence test to the children in those classrooms. In order to find out which school has the highest intelligence level, which of the following should she calculate for each school? a. The variance b. the standard deviation c. the percentile d. the mean
D
A researcher conducts a study to investigate the influence of the amount of noise in the environment on the number of errors a person makes. The following means were obtained. What conclusion should be drawn from this experiment? Low | Med | High x̄=7 | x̄=11 | x̄=14 A. Apparently, there is no relationship between noise level and number of errors. B. Apparently, there is a relationship: as number of errors increases, the noise level also increases from around 7 to around 11 to around 14. C. Apparently, there is a relationship: As the number of errors increases. the noise level also increases from low to medium to high. D. Apparently there is a relationship: As the noise level increases, the number of errors also increases from around 7 to around 11 to around 14.
D
A sampling distribution of means for samples of students taking the SAT exam has a population mean of 500 and a standard error of 200. What proportion of sample means would fall between the population mean and a sample mean of 800? a. .50000 b. .3413 c. .1915 d. .4332
D
A z-score of zero always means that a. the raw score does not exist b. the raw score exists but is negligible c. the raw score almost never occurs d. the raw score is equal to the mean
D
Adding a constant to or substracting a constant from each of the scores in a distribution a. changes the value of the standard deviation by the amount of the constant b. changes the value of the standard deviation by half the amount of the constant c. changes the value of the standard deviation by 34% of the amount of the constant d. does not change the value of the standard deviation
D
Chris wants to calculate a z-score for his own height. The average height in the class is 66 inches, and Chris's height in 62 inches. Chris calculated his z-score to be +1.5. What's wrong with his calculation? A. the z-score is an inappropriate calculation here b. The z-score should be a higher number c. He didn't have the standard deviation d. The z-score should be a negative number
D
Find the median of the scores in the allowing frequency distribution. (S=Score) S | f 9 | 2 8 | 4 7 | 8 6 | 6 5 | 4 4 | 3 3 | 2 A. 8 B. 7 C. 6.21 D. 6
D
Five students took a personality test. Their deviation scores were -4 +3 +1 -2 +2. Assuming that these scores form a normal distribution, which score(s) would have the highest frequency? A. -4 B. +3 C. -2, and +2 D. +1
D
Graphs in book (Chapter 4 #60)
D
How would you describe the following set of scores. 2,2,3,3,3,4,4,5,6,7,7,8,8,8,8,9,9 A. negatively skewed. B. normally distributed. C. positively skewed. D. bimodal.
D
If only the upper 30% of a normally distributed class passed a quiz for which the mean was 70 and the standard deviation was 10, what was the lowest score a student could have received and still have passed? a. 80 b. 64.8 c. 70 d. 75.2
D
If the sample standard deviation (Sx) for a set of data with N=6 is found to be 3.17 then what is the sample variance S²x? a. 3.47 b. 1.78 c. 12.06 d. 10.05
D
If your sense of direction, relative to a sample of college students, gave you a z-score of +1.5 what is your percentile? a. 6th b. 7th c. 43rd d. 93rd
D
In a positively skewed distribution, the estimated population variance (s²x) will be ____________ than the estimated population standard deviation (sx). In a negatively skewed distribution the estimated population variance (s²x) will be _________ than the estimated population standard deviation (sx). A. smaller;smaller b. smaller; larger c. larger; smaller d. larger;larger
D
In an effort to quit smoking, Pat began eating butterscotch hard candies. for the month of September, Pat's mean was 24 pieces of candy per day. What was the total number of butterscotch candies that pat consumed in September? A. 240 B. 460 C. 680 D. 720
D
In order to decide which measure of central tendency is appropriate you must first determine... A. the appropriate graph to use and the independent variable. B. the independent and the dependent variables. C. how the data will be collected. D. the scale of measurement being used and the shape of the distribution.
D
In the language of statistics when we know that a relationship exists between two variables, we can use knowledge of that relationship to a. reduce the variance b. increase the variance c. make sure the variance remains the same d. account for the variance
D
See Diagrams (Chapter 5,#49)
D
Sx and S²x are considered biased estimates for the population standard deviation and variance because, a. they come from sample data b. N for the sample is less than N for the population c. they are not randomly selected d. they reflect the random variability of only N-1 scores
D
The mean is the preferred measure of central tendency when... A. the scale of measurement is interval. B. the scale of measurement is ordinal, interval, or ratio and the distribution is skewed. C. the scale of measurement is ratio. D. the distribution is symmetrical and the scale of measurement is interval or ratio.
D
The mean of a z-score distribution is always ______, and the standard deviation is always ____________. a. 0;10 B. 1;0 C. 100;20 D. 0;1
D
The median is defined as... A. the mostly frequently occurring score. B. the mathematical center of the distribution. C. the smallest deviation from the mean. D. the point at or below which 50% of the scores fall.
D
The proportion of the total area under a normal curve between two z-scores corresponds to the __________ of that range of scores. a. numeric magnitude b. variability c. frequency d. relative frequency
D
The standard deviation is always a. twice as large as the variance b. half as large as the variance c. the square of the variance d. the square root of the variance
D
The sum of the deviations around the mean always equals... A. 1. B. The mean. C. The sum of the total scores. D. 0.
D
To obtain the mean, we would... A. count all the scores and divide by the total number of scores. B. add all the scores and divide by the sum of all the scores. C. divide the total number of scores by the sum of all the scores. D. add all the scores and divide by the total number of scores.
D
What is the estimated population standard deviation (sx) of the following data? SlF 10l4 9l5 8l4 7l0 6l2 5l1 4l1 a. 1.83 b. 3.36 c. 3.16 d. 1.78
D
When computing the variance, why do we square the deviations from the mean? A. To return the units of measure to their original form B. to Compensate for the fact that the number of degrees of freedom is different from N C. To transform the raw scores into squared scores D. To compensate for the fact that deviations about the mean always sum to zero
D
When deciding which typer of measure of central tendency is appropriate, we consider the scale of measurement used to measure the.... A. variability of the distribution. B. Mean. C. Independent variable. D. Dependent variable.
D
When we graph results from an experiment where the independent variable is on a nominal scale, which type of graph os appropriate A. line graph B. Histogram C. Normal curve D. Bar Graph.
D
Which of the following is NOT one of the things the relative frequency of z-scores allows us to calculate for corresponding raw scores? A. Expected relative frequency B. Expected simple frequency C. Percentile rank D. Values in terms of goodness or badness
D
A psychology professor wanted to describe his/her class in terms of the personality characteristic of introversion/extroversion. The population variance was estimated to be 2.56. What does this mean? a. When the professor uses the population mean to predict individuals' scores he/she should expect to be in error by about 2.56 b. When the professor uses the population mean to predict individuals' scores he/she should expect to be more accurate by about 2.56 c. It is impossible to tell because the mean is not known d. The sample mean differs from the population mean by about 2.56
a
A sampling distribution is an approximately normal distribution a. regardless of the shape of the raw score distribution b. only when the shape of the raw score distribution is approximately normal c. only when the raw score population mean is equal to the sample mean d. regardless of the distribution of the sample means
a
According to the central limit theorem, the sampling distribution of means always approximates a ________ distribution. a. normal b. positively skewed c. negatively skewed d. bimodal
a
An academic advisor calculated the mean GPA for college freshmen to be 2.33, with a standard deviation of 1.06. The advisor knows that there is a relationship between high school GPA and freshman-year GPA. If the advisor uses each students high school GPA to predict his/her freshman year GPA, what happens to the average error in prediction relative to not using high school GPA to predict freshman-year GPA? a. The average error will be less b. the average error will be more c. the average error will not change d. There will be no error in prediction
a
For a distribution with x̄=50 and Sx=5, find the raw scores for the following z-scores: -1.2;-.5;1.7;2.6 a. 44.00; 47.50; 58.50; 63.00 b. 20.00;37.50;92.50;115.00 c. 47.32; 48.88; 53.80; 55.81 d. -20.00;-37.50;92.50;115.00
a
For each other the following z-scores, what is the area beyond the z-score in the tail? .63, -1.65, 1.94, -2.27, 2.8 a. .2643; .0495; .0262; .0116; .0026 b. .2643; -.0495; .0262; -.0116; .0026 c. .2357; .4505; .4738; .4884; .4974 d. .2357; -.4505; .4738; -.4884; .4974
a
For the following set of scores, what is the percentile for a score of 24? 23,22,19,25,26,22,19,25,22,20,21,23,23,24,18,20, 22,24,21,21,20,24,22,21,23 a. 84th percentile b. 34th percentile c. 16th percentile d. 50th percentile
a
How accurately the standard normal curve model predicts the actual relative frequency of raw scores depends on three aspects of the data? a. The raw scores form and approximately normal distribution; there is a large sample N; and the raw scores are theoretically continuous scores measured on an interval or ration scale b. 50% of the raw scores are above and below the median; there is a large sample N; and the raw scores are measured on an ordinal, interval or ratio scale. C. 50% of the raw scores are above and below the median; tehre is a moderately large sample N; the raw scores are theoretically continuous scores measured on an interval or ration scale D. The raw scores form an approximately normal distribution; there is a moderately large sample N; and the raw scores are measured on an ordinal, interval or ratio scale
a
If a school's z-score for its sample mean was +3, its percentile rank in the state was a. 99.87% b. 90.87% c. 85.87% d. 95.87%
a
If the sample standard deviation (Sx) for a set of data with N=6 is found to be 3.17 then what would be the estimated population standard deviation (sx)? a.3.47 b.1.78 c.12.06 d.10.05
a
If you see the notation (Σx)² you should a. sum all the xs then square the sum b. square all the xs, then sum the squares c. sum the xs then divide by 2 d. divide all the xs by 2
a
Measures of variability are used to a. summarize and describe the extent to which scores in a distribution differ from one another b. summarize and describe the extent to which scores in a distribution differ from the extreme scores c. make appropriate decisions regarding graph size, shape and style d. summarize and describe measures of central tendency
a
Only the upper 30% of a normally distributed class passed a quiz for which the mean was 70 and the standard deviation was 10. In this class, 76.7 and 78.4 are the boundary limits for students who scored between what percentiles? a. 75th and 80th b. 80th and 85th c. 77th and 80th d. 67th and 80th
a
Sampling distributions of means are always a. approximately normally distributed b. positively skewed c. negatively skewed d. more variable than the population from which the samples were drawn
a
The Greater the the variability in a set of scores, a. the less accurately the scores are represented by one central score b. the more accurately the scores are represented by one central score c. the more similar and consistently close they are to the central score d. the less similar and more consistently close they are to the central score
a
The proper way to describe errors of prediction is to compute a. the variance b. the range c. a z-score d. a T-score
a
The z-score transformation is a useful statistical tool because it enables statisticians to a. compare and interpret scores from virtually any distribution b. determine which scores are the "best" scores c. transform data by multiplying by a constant d. revise the shape of distributions to be more useful
a
The range is the descriptive statistic that indicates the a. distance from the median b. distance between the two most extreme scores c. variability among means d. distance between the mean and extreme scores
b
The term variability is most opposite to a. central tendency b. consistency c. association d. homoscedasticity
b
an evaluation of where a score is located in relation to the other scores in the distribution reflects its a. absolute value b. relative standing c. standard deviation d. frequency
b
A doctor wants to know how well elderly patients remember to take their medicine. The doctor measures the percentage of time during the week that patients remembered to take their medicine. For a sample of 10 populations, what would he/she expect the population variance to be? A. 3.87 b. 15 c. 16.67 d 150
c
Bahatamy academy has an outrageously intelligent student body. In a recent evaluation of all the high schools in the state, Bahatamy Academy received a z-score of +3 for its corresponding sample mean of SAT scores. With a population mean of 500 and a standard deviation (standard error) of 200 for the sampling distribution, what was Bahatamy's sample mean? a. 560 b. 1560 c. 1100 d. 900
c
For each of the following z-scores, what is the area between the mean and each z-score? .4; 1.01; -1.48; -1.89; 2.53 a. .3446; 0.1562; .0694; .0294; .0057 b. .1554; .3438; -.4306; -.4706; .4943 c. .1554; .3438; .4306; .4706; .4943 d. .3446; .1562; -.0694; -.0294; .0057
c
If you see the notation Σx² you should a. Sum all the Xs, then square the sum b. sum the xs, then divide by 2 c. square all the xs, then sum the squares d. divide all the xs by 2
c
In general the larger the value of the standard deviation, a. the less spread out the distribution b. the more tightly packed the distribution around the mean c. the wider the distribution d. the more asymmetrical the distribution
c
Jason's z-score in the 10-K run was -3. If the raw score standard deviation was 5, and the mean running time for the competitors was 55 minute, what was Jason's raw score running time? a. 60 min b. 50 min c. 40 min d. 30 min
c
Measures of central tendency indicate the _________ of a distribution; measures of variability indicate the _________ between the scores in a distribution. a. similarities; difference b. mean; variance c. location; distance d. distance location
c
The proportional improvement that results from using the relationship between two variables to predict scores compared with no using the relationship to predict scores is called a. the sample variance b. the estimated population standard deviation c. the proportion of variance accounted for d. the degrees of freedom
c
The quantity N-1 has a special name. It is known as the a. unbiased estimate b. biased estimate c. degrees of freedom d. freedom of variation
c
The sample mean for a recent introductory psychology test was 78 and the sample variance was 9. Approximately what proportion of the scores was about 81? a. .50 b. .68 c. .16 d. .34
c
The standard deviation of the sampling distribution of means is called the a. percent error of the mean b. likely error of the mean c. standard error of the mean d. special error of the mean
c
The standard deviation, Sx, is a measure of how far scores deviate from a. the median b. each other c. the mean the most frequently occurring score
c
What is the range of the following data? SlF 10l4 9l5 8l4 7l0 6l2 5l1 4l1 a.3 b.5 c. 6 d. 9
c
A group of 10 students participated in a study of nutritional awareness. What is the sample standard deviation (Sx) of their scores? 20,19,22,20,15,18,15,21,19,20 a. 2.21 b. 2.33 c. 4.89 d. 5.43
d
A program evaluator for a large school district wants to know how much intelligence varies in the elementary schools. She randomly selects one classroom at each grade level in each elementary school and administers an intelligence test to the children in those classrooms. If that program evaluator wants to predict how well the students will fare in a city wide Academic Bowl tournament she should: a. calculate the mean and standard deviation for tournament performance b. calculate the variance and standard deviation for intelligence c. calculate the range and the median for both tournament performance and intelligence d. find out if there is a relationship between intelligence level and tournament performance
d
If a sample has a small standard deviation, we can say that the scores in the sample are A. variable b. small c. extreme d. consistent
d
The absolute value is the number is the a. the measure of how much the number is worth b. size of a number only when it is a positive number c. size of a number only when it is a negative number d. numeric magnitude of the number, regardless of whether it is positive of negative
d
Which of the following mathematically indicates the amount a score deviates from the mean? A. Σx B. Σx² C. Σ(x-x̄)/N D. x-x̄
d
Which of the following statements accurately describes the sampling distribution of means? a. The distribution of several sample means when an infinite number of samples of the same size N are randomly selected from one raw score population b. The distribution of all possible sample means when a given finite number of samples of the same size N are randomly selected from one raw score population c. The distribution of all possible sample means when an infinite number of samples of variously sized Ns are randomly selected from several raw score populations d. The distribution of all possible sample means when an infinite number of samples of the same size N are randomly selected from one raw score population
d