Final - MC

What is the first step in the calculation of (ΣX)2? a. Square each score. b. Add the scores. c. Subtract 2 points from each score. d. Add the X - 2 value

add the scores

When does a researcher risk a Type I error? a. anytime H0 is rejected b. anytime H1 is rejected c. anytime the decision is "fail to reject H0" d. All of the other options are correct.

anytime H0 is rejected

A population has μ = 50 and σ = 10. If these scores are transformed into z-scores, the population of z-scores will have a mean of ____ and a standard deviation of ____. a. 50 and 10 b. 50 and 1 c. 0 and 10 d. 0 and 1

0 and 1

If a sample with M = 60 and s = 8 is transformed into z-scores, then the resulting distribution of z-scores will have a mean of ______ and a standard deviation of _____.

0 and 1

Which of the following values is the most reasonable estimate of the standard deviation for the set of scores in the following distribution? (It may help to imagine or sketch a histogram of the distribution.) a. 0 b. 1 c. 3 d. 5 X f 5 1 4 2 3 4 2 2 1 1

1

A set of scores ranges from a high of X = 48 to a low of X = 13. If these scores are placed in a grouped frequency distribution table with an interval width of 5 points, the bottom interval in the table would be _______. a. 13-18 b. 13-19 c. 10-14 d. 10-15

10-14

What is the median for the following set of Scores: 8, 10, 11, 12, 14, 15 a. 11 b. 11.5 c. 12 d. 70 = 11.67

11.5

Each of the following is the sum of the scores for a population of N 5 4 scores. For which population would the definitional formula be a better choice than the computational formula for calculating SS. a. EX=9 b. EX=12 c. EX=15 d. EX=19

12

A distribution with μ = 47 and σ = 6 is being standardized so that the new mean and standard deviation will be μ = 100 and σ = 20. What is the standardized score for a person with X = 56 in the original distribution? a. 110 b. 115 c. 120 d. 130

130

What is the value of SS, the sum of the squared deviations, for the following population of N = 4 scores? Scores: 1, 4, 6, 1 a. 0 b. 18 c. 54 d. 122^2 144

18

How many scores in the distribution are used to compute the range? a. only 1 b. 2 c. 50% of them d. all of the scores

2

What is the mode for the following set of n 5 8 scores? Scores: 0, 1, 1, 2, 2, 2, 2, 3 a. 2 b. 2.5 c. 13 = 1.625 8 d. 13

2

What is the standard deviation for the following population of scores? Scores: 1, 3, 7, 4, 5 a. 20 b. 5 c. 4 d. 2

2

In a correlational study, how many variables are measured for each individual and how many groups of scores are obtained? a. 1 variable and 1 group b. 1 variable and 2 groups c. 2 variables and 1 group d. 2 variables and 2 groups

2 variables and 1 group

Which of the following sets of scores has the greatest variability? a. 2, 3, 7, 12 b. 13, 15, 16, 17 c. 24, 25, 26, 27 d. 42, 44, 45, 46

2,3,7,12

After 5 points are added to every score in a distribution, the mean is calculated and found to be μ = 30. What was the value of the mean for the original distribution? a. 25 b. 30 c. 35 d. Cannot be determined from the information given

25

What is the mean for the population of scores shown in the frequency distribution table? a. 15/10 b. 15/5 c. 29/10 d. 29/5

29/10

For the following frequency distribution, how many individuals had a score of X = 2? a. 1 b.2 c. 3 d. 4 X f 5 1 4 2 3 4 2 3 1 2

3

For the sample shown in the frequency distribution table, what is the mode? a. 3 b. 3.5 c. 4 d.5 X f 5 1 4 3 3 4 2 2 1 1

3

What is the mean for the following sample of scores? Scores: 1, 2, 5, 4 a. 12 b. 6 c. 4 d. 3

3

What is the variance for the following sample of n 5 4 scores? Scores; 2, 5, 1, 2 a. 34/3 = 11.33 b. 9/4 = 2.25 c. 9/3=3 d. sqrt of 3 = 173

3

For the sample shown in the frequency distribution table, what is the median? a. 3 b. 3.5 c. 4 d. 15/2 X f 5 1 4 5 3 4 2 1 1 1

3.5

For this distribution, how many individuals had scores lower than X = 20? a. 2 b. 3 c. 4 X f 24-25 2 22-23 4 20-21 6 18-19 3 16-17 1

4

One sample has n=8 scores and M=2. A second sample has n= 4 scores and M = 8. If the two samples are combined, then what is the mean for the combined sample? a. 3 b. 4 c. 5 d. 6

4

For the following frequency distribution, what is ΣX^2? a. 30 b. 45 c. 77 d. 289 X f 4 1 3 2 2 2 1 3 0 1

45

The following is a distribution of quiz scores. If a score of X = 2 or lower is failing, then how many individuals failed the quiz? a. 2 b. 3 c. 5 d. 9 X f 5 1 4 2 3 4 2 3 1 2

5

In a grouped frequency distribution one interval is listed as 20-24. Assuming that the scores are measuring a continuous variable, what is the width of this interval? a. 3 points b. 4 points c. 5 points d. 54 points

5 points

A population of scores has σ = 4. In this population, an X value of 58 corresponds to z = 2.00. What is the population mean? a. 54 b. 50 c. 62 d. 66

50

A researcher selects all the possible samples with n= 3 scores from a population and computes the sample variance, dividing by n - 1, for each sample. If the population variance is o^2 = 6, then what is the average value for all of the sample variances? a. 6 b. greater than 6 c. less than 6 d. impossible to determine

6

What is the value of Σ(X - 2) for the following scores: 6, 2, 4, 2? a. 12 b. 10 c. 8 d. 6

6

When measuring height to the nearest half inch, what are the real limits for a score of 68.0 inches? a. 67 and 69 b. 67.5 and 68.5 c. 67.75 and 68.75 d. 67.75 and 68.25

67.75 and 68.25

A population of scores has σ = 10. In this population, a score of X = 60 corresponds to z = −1.50. What is the population mean? a. −30 b. 45 c. 75 d. 90

75

A population of scores has μ = 44. In this population, an X value of 40 corresponds to z = −0.50. What is the population standard deviation? a. 2 b. 4 c. 6 d. 8

8

What is the median for the following set of scores: Scores: 3, 4, 6, 8, 9, 10, 11 a. 7 b. 7.5 c. 8 d. 8.5

8

What is the value of SS, the sum of the squared deviations, for the following sample? Scores: 1, 4, 0, 1 a. 36 b. 18 c. 9 d. 3

9

What is the range for the following set of scores? 3, 7, 9, 10, 12 a. 3 points b. 4 or 5 points c. 9 or 10 points d. 12 points

9 or 10 points

Which of the following is most likely to reject the null hypothesis even if the treatment effect is very small? a. A small sample and a small value for σ. b. A small sample and a large value for σ. c. A large sample and a small value for σ. d. A large sample and a large value for σ

A large sample and a small value for σ

One item on a questionnaire asks, "How many siblings (brothers and sisters) did you have when you were a child?" A researcher computes the mean, the median, and the mode for a set of n 5 50 responses to this question. Which of the following statements accurately describes the measures of central tendency? a. Because the scores are all whole numbers, the mean will be a whole number. b. Because the scores are all whole numbers, the median will be a whole number. c. Because the scores are all whole numbers, the mode will be a whole number. d. All of the other options are correct description

Because the scores are all whole numbers, the mode will be a whole number

Last week Sarah had a score of X = 43 on a Spanish exam and a score of X = 75 on an English exam. For which exam should Sarah expect the better grade? a. Spanish b. English c. The two grades should be identical. d. Impossible to determine without more information

Impossible to determine without more information

A sample of n = 16 individuals is selected from a population with μ = 80 and σ = 5, and a treatment is administered to the sample. If the treatment really does have an effect, then what would be the effect of increasing the standard deviation to σ = 25? a. Increase the chances that the sample will produce an extreme z-score and increase the likelihood that you will conclude that a treatment effect exists. b. Increase the chances that the sample will produce an extreme z-score and increase the likelihood that you will conclude that a treatment effect does not exist. c. Increase the chances that the sample will produce a z-score near zero and increase the likelihood that you will conclude that a treatment effect exists. d. Increase the chances that the sample will produce a z-score near zero and increase the likelihood that you will conclude that a treatment effect does not exist

Increase the chances that the sample will produce a z-score near zero and increase the likelihood that you will conclude that a treatment effect does not exist

A sample of n = 16 individuals is selected from a population with μ = 40 and σ = 12, and a treatment is administered to the sample. After treatment, the sample mean is M = 42. How does this sample compare to samples that should be obtained if the treatment has no effect? a. It is an extreme value that would be very unlikely if the treatment has no effect. b. It is much the same as samples that would be obtained if the treatment has no effect. c. The mean is noticeably larger than would be expected if the treatment has no effect but it is not quite an extreme sample. d. There is no way to compare this sample with those that would be obtained if the treatment had no effect.

It is much the same as samples that would be obtained if the treatment has no effect.

For which of the following pairs of distributions would the mean difference be easiest to see? a.M =45 with s = 5 compared to M = 50 with s = 5. b.M = 45 with s = 5 compared to M = 55 with s = 5. c.M = 45 with s = 10 compared to M = 50 with s = 10. d.M = 45 with s = 10 compared to M = 55 with s = 10.

M = 45 with s = 5 compared to M = 55 with s = 5

During the month of October, an instructor recorded the number of absences for each student in a class of n 5 20 and obtained the following distribution. What are the values for the mean, the median, and the mode for this distribution? ... # of absences f 5 1 4 2 3 7 2 5 1 3 0 2

Mean = 2.35, Median = 2.5, Mode = 3

Which of the following is an advantage of transforming X values into z-scores? a. All negative numbers are eliminated. b. The distribution is transformed to a normal shape. c. All scores are moved closer to the mean. d. None of the other options is an advantage

None of the other options is an advantage

What is the correct decision in a hypothesis if the data produce a z-score that is in the critical region? a. Reject H0 b. Fail to reject H0 c. Reject H1 d. Fail to reject

Reject H0

What is meant by a biased statistic. a. The average value for the statistic overestimates the corresponding population parameter. b. The average value for the statistic underestimates the corresponding population parameter. c. The average value for the statistic either overestimates or underestimates the corresponding population parameter. d. The average value for the statistic is exactly equal to the corresponding population parameter

The average value for the statistic either overestimates or underestimates the corresponding population parameter

Under what circumstances would a score that is above the mean by 5 points appear to be very close to the mean? a. When the mean is much greater than 5 b. When the mean is much less than 5 c. When the standard deviation is much greater than 5 d. When the standard deviation is much less than 5

When the standard deviation is much greater than 5

A distribution with μ = 35 and σ = 8 is being standardized so that the new mean and standard deviation will be μ = 50 and σ = 10. In the new, standardized distribution your score is X = 60. What was your score in the original distribution? a. X = 45 b. X = 43 c. X=1.00 d. impossible to determine without more information

X=43

What is a likely outcome for a hypothesis test if a treatment has a very small effect? a. a Type I error b. a Type II error c. correctly reject the null hypothesis d. correctly fail to reject the null hypothesis

a Type II error

A distribution is positively skewed. Which is the most probable order for the three measures of central tendency? a. mean = 40, median = 50, mode = 60 b. mean = 60, median = 50, mode = 40 c. mean = 40, median = 60, mode = 50 d. mean = 50, median = 50, mode = 50

mean = 60, median = 50, mode = 40

Which of the following is true for a symmetrical distribution? a. the mean, median, and mode are all equal b. mean = median c. mean = mode d. median = mode

mean = median

An operational definition is used to____________a hypothetical construct. a. define b. measure c. measure and define d. None of the other choices is correct.

measure and define

Using z-scores, a population with μ = 37 and σ = 6 is standardized so that the new mean is μ = 50 and σ = 10. How does an individual's z-score in the new distribution compare with his/her z-score in the original population? a. new z =old z+13 b. new z = (10/6)(old z) c. new z=old z d. cannot be determined with the information given

new z=old z

The teacher in a communications class asks students to identify their favorite real- ity television show. The different television shows make up a scale of measurement. a. nominal b. ordinal c. interval d. ratio

nominal

A research study comparing alcohol use for college students in the United States and Canada reports that more Canadian students drink but American students drink more (Kuo, Adlaf, Lee, Gliksman, Demers, and Wechsler, 2002). What research design did this study use? a. correlational b. experimental c. nonexperimental d. noncorrelational

non experimental

A researcher is curious about the average IQ of registered voters in the state of Florida. The entire group of registered voters in the state is an example of a ___________ a. sample b. statistic c. population d. parameter

population

If a frequency distribution graph is drawn as a smooth curve, it is probably showing a ______ distribution. a. sample b. population c. skewed d. symmetric

population

A set of scores is presented in a frequency distribution histogram. If the histogram shows a series of bars that tend to decrease in height from left to right, then what is the shape of the distribution? a. symmetrical b. positively skewed c. negatively skewed d. normal

positively skewed

A population has a mean of u= 35 and a standard deviation of o = 5. After 3 points are added to every score in the population, what are the new values for the mean and standard deviation? a. u= 35 and o=5 b. u= 35 and o= 8 c. u=38 and o= 5 d.u=38 and o= 8

u=38 and o= 5

For a population with μ = 100 and σ = 20, what is the z-score corresponding to X = 105? a. +0.25 b. +0.50 c. +4.00 d. +5.00

+.25

For a sample with a standard deviation of s = 5, what is the z-score corresponding to a score that is located 10 points below the mean? a. −10 b. +2 c. −2 d. cannot answer without knowing the mean

-2

For a sample with M = 60 and s = 8, what is the z-score corresponding to X = 62? a. 2 b. 4 c. 0.25 d. 0.50

.25

What is the variance for the following set of scores? 2, 2, 2, 2, 2 a. 0 b. 2 c. 4 d. 5

0

If other factors are held constant, then how does the size of the standard deviation affect the likelihood of rejecting the null hypothesis and the value for Cohen's d? a. A larger standard deviation increases the likelihood of rejecting the null hypothesis and increases the value of Cohen's d. b. A larger standard deviation increases the likelihood of rejecting the null hypothesis but decreases the value of Cohen's d. c. A larger standard deviation decreases the likelihood of rejecting the null hypothesis but increases the value of Cohen's d. d. A larger standard deviation decreases the likelihood of rejecting the null hypothesis and decreases the value of Cohen's d.

A larger standard deviation decreases the likelihood of rejecting the null hypothesis and decreases the value of Cohen's d

How is the standard deviation represented in a frequency distribution graph? a. By a vertical line located at a distance of one standard deviation above the mean. b. By two vertical lines located one standard deviation above the mean and one standard deviation below the mean. c. By a horizontal line or arrow extending from a location one standard deviation above the mean to a location one standard deviation below the mean. d. By a horizontal line or arrow extending from the mean for a distance equal to one standard deviation

By a horizontal line or arrow extending from the mean for a distance equal to one standard deviation

A teacher gave a reading test to a class of 5th-grade students and computed the mean, median, and mode for the test scores. Which of the following statements cannot be an accurate description of the scores? a. The majority of the students had scores above the mean. b. The majority of the students had scores above the median. c. The majority of the students had scores above the mode. d. All of the other options are false statement

The majority of the students had scores above the median

What symbols are used for the mean and standard deviation for a sample in a research report? a. The mean is identified by the letter M and the standard deviation is represented by a lowercase s. b. The mean is identified by the letter M and the standard deviation is represented by SD. c. The mean is identified by a lowercase letter m and the standard deviation is represented by a lowercase s. d. The mean is identified by a lowercase letter m and the standard deviation is represented by SD.

The mean is identified by the letter M and the standard deviation is represented by SD

A research report summarizes the results of the hypothesis test by stating, "z = 2.13, p < .05." Which of the following is a correct interpretation of this report? a. The null hypothesis was rejected and the probability of a Type I error is less than .05. b. The null hypothesis was rejected and the probability of a Type II error is less than .05. c. The null hypothesis was not rejected and the probability of a Type I error is less than .05. d. The null hypothesis was not rejected and the probability of a Type II error is less than .05

The null hypothesis was rejected and the probability of a Type I error is less than .05

A researcher administers a treatment to a sample of n = 25 participants and uses a hypothesis test to evaluate the effect of the treatment. The hypothesis test produces a z-score of z = 1.77. Assuming that the researcher is using a two-tailed test, a. The researcher should reject the null hypothesis with α = .05 but not with α = .01. b. The researcher should reject the null hypothesis with either α = .05 or α = .01. c. The researcher should fail to reject H0 with either α = .05 or α = .01. d. Cannot answer without additional information

The researcher should fail to reject H0 with either α = .05 or α = .01.

A researcher expects a treatment to produce an increase in the population mean. The treatment is evaluated using a one-tailed hypothesis test, and the test produces z = -1.85. Based on this result, what is the correct statistical decision? a. The researcher should reject the null hypothesis with α = .05 but not with α = .01. b. The researcher should reject the null hypothesis with either α = .05 or α = .01. c. The researcher should fail to reject H0 with either α = .05 or α = .01. d. Cannot answer without additional information

The researcher should fail to reject H0 with either α = .05 or α = .01.

Which of the following is not an assumption for the z-score hypothesis test? a. The observations must be independent. b. The value for μ must be the same after treatment as it was before treatment. c. The value for σ must be the same after treatment as it was before treatment. d. The sample must be obtained by random sampling

The value for μ must be the same after treatment as it was before treatment

A group of quiz scores ranging from 4-9 are shown in a histogram. If the bars in the histogram gradually increase in height from left to right, what can you conclude about the set of quiz scores? a. There are more high scores than there are low scores. b. There are more low scores than there are high scores. c. The height of the bars always increases as the scores increase. d. None of the above

There are more high scores than there are low scores

If sample variance is computed by dividing by n, instead of n 2 1, how will the obtained values be related to the corresponding population variance. a. They will consistently underestimate the population variance. b. They will consistently overestimate the population variance. c. The average value will be exactly equal to the population variance. d. The average value will be close to, but not exactly equal to, the population variance

They will consistently underestimate the population variance

The seminar rooms in the library are identified by letters (A, B, C, and so on). A professor records the number of classes held in each room during the fall semester. If these values are presented in a frequency distribution graph, what kind of graph would be appropriate? a. a histogram b. a polygon c. a histogram or a polygon d. a bar graph

bar graph

Which of the following is an example of an unbiased statistic. a. the sample mean b. the sample variance (dividing by n - 1) c.both the sample mean and the sample variance (dividing by n - 1) d. neither the sample mean nor the sample variance (dividing by n - 1)

both the sample mean and the sample variance (dividing by n - 1)

A treatment is administered to a sample selected from a population with a mean of μ = 80 and a standard deviation of σ = 10. After treatment, the sample mean is M = 85. Based on this information, the effect size as measured by Cohen's d is _____. a. d = 5.00 b. d = 2.00 c. d=0.50 d. impossible to calculate without more information

d=0.50

3. Statistical techniques that summarize, organize, and simplify data are classified as . a. population statistics b. sample statistics c. descriptive statistics d. inferential statistics

descriptive statistics

In general, ___________statistical techniques are used to summarize the data from a research study and ____________statistical techniques are used to determine what conclusions are justified by the results. a. inferential, descriptive b. descriptive, inferential c. sample, population d. population, sample

descriptive,inferential

A researcher studies the factors that determine the number of children that couples decide to have. The variable, number of children, is an example of a variable. a. discrete b. continuous c. nominal d. ordinal

discrete

Which of the following defines a Type II error? a. rejecting a false null hypothesis b. rejecting a true null hypothesis c. failing to reject a false null hypothesis d. failing to reject a true null hypothesis

failing to reject a false null hypothesis

In N = 25 games last season, the college basketball team averaged μ = 74 points with a standard deviation of σ = 6. In their final game of the season, the team scored 90 points. Based on this information, the number of points scored in the final game was _____. a. a little above average b. far above average c. above average, but it is impossible to describe how much above average d. There is not enough information to compare last year with the average

far above average

For a negatively skewed distribution with a mode of X = 25 and a median of 20, the mean is probably _____. a. greater than 25 b. less than 20 c. between 20 and 25 d. cannot be determined from the information given

less than 20

IQ tests are standardized so that the average score is 100 for the entire group of people who take the test each year. However, if you selected a group of 20 people who took the test and computed their average IQ score you probably would not get 100. What statistical concept explains the difference between your mean and the mean for the entire group? a. statistical error b. inferential error c. descriptive error d. sampling error

sampling error

A researcher is interested in the sleeping habits of American college students. A group of 50 students is interviewed and the researcher finds that these students sleep an average of 6.7 hours per day. For this study, the average of 6.7 hours is an example of a(n)________ a. parameter b. statistic c. population d. sample

statistic

In a distribution of exam scores, which of the following would be the highest score? a. the 20th percentile b. the 80th percentile c. a score with a percentile rank of 15% d. a score with a percentile rank of 75%

the 80th percentile

Standard deviation is probably the most commonly used value to describe and measure variability. Which of the following accurately describes the concept of standard deviation? a. the average distance between one score and another b. the average distance between a score and the mean c. the total distance from the smallest score to the largest score d. one half of the total distance from the smallest score to the largest score

the average distance between a score and the mean

Stephens, Atkins, and Kingston (2009) found that participants were able to tolerate more pain when they shouted their favorite swear words over and over than when they shouted neutral words. For this study, what is the independent variable? a. the amount of pain tolerated b. the participants who shouted swear words c. the participants who shouted neutral words d. the kind of word shouted by the participants

the kind of word shouted by the participants

The value of one score in a distribution is changed from X = 20 to X = 30. Which measure(s) of central tendency is (are) certain to be changed? a. The mean b. The median c. The mean and the median d. The mode

the mean

What value is represented by the lowercase letter n? a. the number of scores in a population b. the number of scores in a sample c. the number of values to be added in a summation problem d. the number of steps in a summation problem

the number of scores in a sample

A sample has a mean of M = 45. If one person with a score of X = 53 is removed from the sample, what effect will it have on the sample mean? a. The sample mean will increase. b. The sample mean will decrease. c. The sample mean will remain the same. d. Cannot be determined from the information given

the sample mean will decrease

Under what circumstances would a score that is 15 points above the mean be considered to be near the center of the distribution? a. when the population mean is much larger than 15 b. when the population standard deviation is much larger than 15 c. when the population mean is much smaller than 15 d. when the population standard deviation is much smaller than 15

when the population standard deviation is much larger than 15

Under what circumstances would a score that is 20 points above the mean be considered to be an extreme, unrepresentative value? a. when the population mean is much larger than 20 b. when the population standard deviation is much larger than 20 c. when the population mean is much smaller than 20 d. when the population standard deviation is much smaller than 20

when the population standard deviation is much smaller than 20

A researcher is predicting that a treatment will increase scores. If this treatment is evaluated using a directional hypothesis test, then the critical region for the test ______. a. would be entirely in the right-hand tail of the distribution b. would be entirely in the left-hand tail of the distribution c. would be divided equally between the two tails of the distribution d. cannot answer without knowing the value of the alpha level

would be entirely in the right-hand tail of the distribution

Of the following z-score values, which one represents the location closest to the mean? a. z = +0.50 b. z = +1.00 c. z=−1.00 d. z = −2.00

z=+.50

Of the following z-score values, which one represents the most extreme location on the left-hand side of the distribution? a. z = +1.00 b. z = +2.00 c. z=−1.00 d. z = −2.00

z=-2.00

If your exam score is X = 60, which set of parameters would give you the best grade? a. μ = 65 and σ = 5 b. μ = 65 and σ = 2 c. μ = 70 and σ = 5 d. μ = 70 and σ = 2

μ = 65 and σ = 5

A researcher selects a sample of n = 20 from a normal population with μ = 80 and σ = 20, and a treatment is administered to the sample. If a hypothesis test is used to evaluate the effect of the treatment, what is the null hypothesis? a. μ = 80 b. M = 80 c. μ not equal 80 d. M not equal 80

μ = 80

A sample is selected from a population with a mean of μ = 45 and a treatment is administered to the sample. If the treatment is expected to produce a decrease in the scores, then what would be the null hypothesis for a directional hypothesis test? a. μ ≥ 45 b. μ ≤ 45 c. M≤45 d. M ≥ 45

μ ≥ 45

For a distribution of exam scores with μ = 70, which value for the standard deviation would give the highest grade to a score of X = 75? a. σ = 1 b. σ = 2 c. σ = 5 d. σ = 10

σ = 1

A population with μ = 85 and σ = 12 is transformed into z-scores. After the transformation, the population of z-scores will have a standard deviation of _____ a. σ = 12 b. σ = 1.00 c. σ = 0 d. cannot be determined from the information given

σ = 1.00