Final Exam

the sampling distribution of the mean gives... a. all the values the same mean can take b. the probability of getting each value if sampling is random from the H0 population c. all the values the sample standard deviation can take d. the probability of getting each standard deviation value if sampling is random from the H0 population e. a and b

e. a and b

In stating H0 and H1, one must be certain that they are... a. mutually exclusive b. independent c. exhaustive d. a series of N trials e. a and c

e. a and c

what does the standard deviation measure? a. the average values b. variability c. the average deviation of scores about the mean d. both b and c

d. both b and c

when the relation between X and Y is perfect, the prediction of Y given X is ____. a. perfect b. always equal to Y c. impossible to determine d. approximate

a. perfect

what is the standard deviation for the following set of scores: 8, 8, 8, 8

0

7. The brand of car you drive is measured on a(n) _____ scale. a. nominal b. ordinal c. interval d. ratio

a. nominal

Which of the following is NOT a continuous variable? a. number of students in the class b. temperature c. height d. weight e. all the above

a. number of students in the class

How healthy a person feels is an example of a/an ______ scale a. ordinal b. ratio c. nominal d. interval

a. ordinal

if Sy/x = 0.00, the relationship between the variables is ____. a. perfect b. imperfect c. curvilinear d. unknown

a. perfect

Population is to parameter as sample is to a. variable b. data c. statistic d. constant

c. statistic

9. The measurement scale with the absolute zero point is the _____ scale. a. nominal b. ordinal c. interval d. ratio

d. ratio

inferential statistics a. are the same as descriptive statistics b. also uses methods of descriptive statistics c. allows one to make inferences about a population based on sample data d. allows one to make inferences about a sample based on population data e. b and c

e. b and c

If a test is a robust test... a. it is sensitive to its underlying mathematical assumptions b. it doesn't estimate any population parameters c. it is insensitive to its underlying mathematical assumptions d. it often may be used despite violations of its underlying mathematical assumptions e. c and d

e. c and d

The average (mean) IQ of all students in the U.S. is called a

parameter

The average (mean) IQ of the 22,000 students is called a

statistic

8. Professor rankings are measured on a(n)__________scale. a. nominal b. ordinal c. interval d. ratio

b. ordinal

A normally distributed set of population scores has a mean of 65 and a standard deviation of 10.2. The standard error of the mean, for samples of size 48 equals... a. 1.47 b. 10.2 c. 65 d. none of the above

a. 1.47

if the value of Sy/x= 4.00 for relationship A and Sy/x = 5.25 for relationship B, in which relationship would you have the most confidence in a particular prediction? a. A b. B c. it makes no difference d. cannot be determined for the information given

a. A

the ____ sums of squares measures the variability of the observed values around their respective means a. Treatment/Between groups b. error/within groups c. interaction d. total

a. Treatment/Between groups

In the t test for independent groups, the unbiased estimate of the population variance is.. a. a weighted average of S1 squared and S2 squared b. S2 squared alone c. S1 squared alone d. non of the above

a. a weighted average of S1 squared and S2 squared

If a correlation is perfect, a. all the points must fall on a straight line b. all the points must fall on a curve line c. most the points must fall on the line, but some can miss it d. none of the points fall on a straight line

a. all the points must fall on a straight line

a sample size increases, standard deviation about the mean a. decreases b. increases c. stays the same d. approaches standard deviation

a. decreases

Which of the following is a continuous variable? a. distance between one's eyes b. class size c. incidence of car accidents d. number of friends

a. distance between one's eyes

Two events are independent if... a. the occurrence of one has no effect on the probability of occurrence of another b. the occurrence of one precludes the occurrence of another c. the occurrence of one substantially alters the probability of occurrence of another d. the sum of their probabilities equals one

a. the occurrence of one has no effect on the probability of occurrence of another

A ____ attempts to determine if changes in one variable produce changes in another variable. a. true experiment b. correlational study c. naturalistic observation d. parameter estimation

a. true experiment

The proportion of scores less than z = 0.00 is a. 0.00 b. 0.50 c. 1.00 d. -0.50 e. impossible to compute from the information given

b. 0.50

If one or both variables are ordinal scaled and the relationship is linear, what type of the correlation coefficient is most appropriate? a. Pearson r b. Spearman rho c. Phi d. Eta

b. Spearman rho

if the correlation between two sets of scores is 0 and one had to predict the value of Y for any given value of X, the best prediction of Y would be ___. a. bY b. Y bar c. 0 d. X bar

b. Y bar

When analyzing data from experiments that involve more than two groups... a. doing t tests on all possible pairs of means increases the probability of making a Type II error b. doing t tests on all possible pairs of means increases the probability of making a Type I error c. it is generally permissible to do t tests between all possible pairs of means and use student's t distribution d. doing t tests on all possible pairs of means decrease the probability of making Type I errors

b. doing t tests on all possible pairs of means increases the probability of making a Type I error

the ____ sums of squares measures the variability of the sample treatment means around the overall mean a. Treatment/Between groups b. error/within groups c. interaction d. total

b. error/within groups

A distribution of raw scores is positively skewed. You want to transform it so that it is normally distributed. Your friend, who fancies herself a statistic whiz, advises you to transform the raw scores to z scores; that the z scores will be normally distributed. You should a. ignore the advice because your friend flunked her last statistics test b. ignore the advice because z distributions have the same shape as the raw scores c. take the advice because z distributions are always normally distributed d. take the advice because z distributions are always normally distributed

b. ignore the advice because z distributions have the same shape as the raw scores

What are the real limits of the observation of 220 pounds? a. may be anywhere in the range of 219 to 221 pounds b. may be anywhere in the range of 219.5 to 220.5 pounds c. 221 pounds d. may be anywhere in the range of 219.95 to 220.05 pounds

b. may be anywhere in the range of 219.5 to 220.5 pounds

Which of the following statements is false? a. independent variable- variable that is systematically manipulated by the investigator b. sample- complete set of objects, individuals, or scores that the investigator is interested in studying c. statistic- number calculated on sample data that quantifies a characteristic of the sample d. data- measurements made on the subjects in an experiment

b. sample- complete set of objects, individuals, or scores that the investigator is interested in studying

student's t test for correlated groups really reduces to... a. the sign test b. student's t test for single samples using different scores c. student's t test for independent groups d. non of the above

b. student's t test for single samples using different scores

if the alternative hypothesis states that studying effects grade point average, the null hypothesis state... a. studying does not increase grade point average b. studying has no effect on grade point average c. studying increases GPA d. P doesn't equal Q

b. studying has no effect on grade point average

which of the following is NOT a property of the mean? a. the mean is sensitive to the exact value of all of the scores b. the mean is the most subject to sampling variation c. the sum of the deviations about the mean equals zero d. the sum of the squared deviations about the mean is a minimum e. the mean is most affected by extreme scores

b. the mean is the most subject to sampling variation

which of the following statements concerning Pearson r is NOT true a. r= 0.00 represents the absence of a relationship b. the relationship between the two variables must be nonlinear c. r= 0.76 has the same predictive power as r= -0.76 d. r= 1.00 represents a perfect relationship e. all the above are true

b. the relationship between the two variables must be nonlinear

a correlation between college entrance exam grades and scholastic achievement was found to be -1.08. On the basis of this you would tell the university that ____. a. the entrance exam is a good predictor of success b. they should hire a new statistician c. the exam is a poor predictor of success d. students who do best on the exam will make the worst students e. students at this school are underachieving

b. they should hire a new statistician

the advantage of a powerful experiment is that... a. the probability of a Type I error is reduced b. you are more likely to detect the real effects of the independent variable, if there are any c. as power increases, alpha increases d. as power increases, N increases

b. you are more likely to detect the real effects of the independent variable, if there are any

What is the correct rounding of 3.2350 to two decimal places? a. 3.23 b. 3.2 c. 3.24 d. 3.205

c. 3.24

a normally distributed set of population scores has a mean of 65 and a standard deviation of 10.2. The mean of the sampling distribution of the mean, for samples of size 48 equals.... a. 1.47 b. 10.2 c. 65 d. non of the above

c. 65

An experiment is conducted to determine if lack of sleep influences memory of college students. What is the independent variable? a. Memory b. Type of student c. Amount of sleep d. Not enough information given

c. Amount of sleep

A posteriori probability refers to.. a. a probability value deduced from reason alone b. low priority probability c. a probability value determined after collecting data d. none of the above

c. a probability value determined after collecting data

correlation and regression differ in that ____. a. correlation is primarily concerned with the size and direction of relationships b. regression is primarily used for prediction c. both of these are true d. neither of these are true

c. both of these are true

Descriptive statistics are used to a. allow one to make inferences about a population based on sample data b. describe a sample, but not a population c. calculate measures of central tendency of a set of scores d. more than one of the above answers is correct

c. calculate measures of central tendency of a set of scores

You read in a newspaper that 35% of all college students have two or more active credit cards. This is an example of a(n) a. descriptive statistic b. independent variable c. inferential statistic d. constant

c. inferential statistic

the alpha level a. is always set at 0.05 or 0.01 b. is set after the data are analyzed c. is determined by the consequences of making a Type I and Type II error d. depends on N

c. is determined by the consequences of making a Type I and Type II error

10. Which of these is a discrete variable? a. miles walked in a week b. hours studied per day c. number of cars passed in the last 10 miles d. your weight in the morning

c. number of cars passed in the last 10 miles

A distribution has a mean of 89 and a median of 70. This distribution is, a. symmetrical b. negatively skewed c. positively skewed d. not enough information given

c. positively skewed

in employing a correlated groups design, one possible drawback is, a. the increased number of statistical computations b. random errors are likely to be greater c. reduction in degrees of freedom d. none of the above

c. reduction in degrees of freedom

In order to estimate the attention level of college undergraduates in the United States, a psychologist measures the attention span of the undergraduates at a local university. The undergraduates at the local university are a _____________ a. parameter b. population c. sample d. statistic

c. sample

Which of the following is an example of inferential statistics? a. computing the mean score on the Psyc 241 exam b. creating a frequency distribution of UND student ages c. surveying a sample of ND residents about their attitude toward the governor d. computing the standard deviation of the income of Grand Forks residents

c. surveying a sample of ND residents about their attitude toward the governor

sum( Y - Y')2 represents: a. the variance b. the standard error of the estimate c. the total error of prediction d. the standard deviation

c. the total error of prediction

If bY is negative, higher values of X are associated with ____. a. Lower scores of X' b. Higher values of Y c. Higher values of (Y-Y') d. Lower values of Y

d. Lower values of Y

Reaction time would be measured on what type of scale? a. nominal b. ordinal c. interval d. ratio

d. ratio

If you retain a null hypothesis, you may be making... a. a Type II error b. a Type I error c. a correct decision d. a and c d. b and c

d. a and c

A priori comparisons... a. are planned in advance of the experiment b. often arise out of theory and priori research c. may be done without obtaining a significant F in the one-way ANOVA d. all of the above

d. all of the above

As N gets _______ the critical value of t gets ___________ a. larger; larger b. smaller; smaller c. larger; smaller d. both c and d

d. both c and d

6. The number of people visiting the Lewis and Clark exhibit was 7492. The real limits of that measurement are a. between 7491.5 and 7492.5 people b. between 7491.99 and 7492.01 people c. between 7490 and 7495 people d. exactly 7492 people (it's a discrete variable)

d. exactly 7492 people (it's a discrete variable)

Rebecca was asked to measure the number of plastic straws used on the island of Roatan Honduras after their "no plastic straw" campaign. The appropriate measurement scale Rebecca would use is: a. nominal b. ordinal c. interval d. ratio

d. ratio

A statistic describes a(n) _____________, while a parameter describes a(n) ____________. a. population, dependent variable b. population, sample c. variable, sample d. sample, population

d. sample, population

When you analyze sample data, you calculate a a. variable b. parameter c. constant d. statistic

d. statistic

if alpha has changed from 0.05 to 0.01,.... a. the probability of Type II error decreases b. the probability of Type I error increases c. the error probabilities stay the same d. the probability of Type II error increases

d. the probability of Type II error increases

one employs a correlated groups design.... a. to eliminate random error b. to specify calculations c. for prediction d. to reduce the effects of the individual differences among subjects

d. to reduce the effects of the individual differences among subjects

Which of the following statement(s) is (are) an important consideration(s) in applying liner regression techniques? a. the relationship should be linear b. both variables must be measured in the same units c. predictions for Y should be within the range of the Xx variable in the sample d. all of the above e. a and c

e. a and c

which of the following would cause Fobt to increase? a. an increase in the difference between the means b. an increase in the the within-groups variability c. an increase in the magnitude of the independent variable's effect d. a and b e. a and c

e. a and c

If alpha is changed from 0.01 to 0.05.... a. the probability we will retain a false H0 increases b. the probability of Type II error decreases c. the probability of Type I error increases d. the error probabilities stay the same e. b and c

e. b and c

If you reject the null hypothesis, you may be making.... a. a Type II error b. a Type I error c. a correct decision d. a and c e. b and c

e. b and c