Test Two
All bell-shaped curves _________.
Are symmetrical
If the alpha level is changed from 0.05 to 0.01, what effect does this have on beta?
Beta increases
If the probability of drawing a member of a population is not equal for all members, then the sample is said to be _________.
Biased
How much would your income be if its z score value was 2.58?
Cannot be determined from information given
The z score corresponding to a raw score of 120 is _________.
Impossible to compute from the information given
A set of events is exhaustive if _________.
The set includes all of the possible events
A z score is a transformed score.
True
The sign test _________.
a, b, and c
In a normal curve, the inflection points occur at _________.
u+-1a
If the value of rho for a set of ordinal data equaled 0.68, the value of r for the same data would be 0.68.
False
In a linear relationship all the points must fall on a straight line.
False
The alpha level _________.
Is determined by the consequences of making a Type I and Type II error
One can say it is always preferable to make a Type II error.
It depends on the costs of making a Type I or Type II error
For any given obtained result, a one tail p-level is
Less than the two tail p-level and is appropriate to use only if the alternative hypothesis is directional.
Pearson r can be properly used on which of the following type(s) of relationships?
Linear
A set of raw scores has a rectangular shape. The z transformed scores for this set of raw scores has a _________ shape.
Rectangular
If one takes a sample of pairs of points over a narrow range of X or Y scores, what effect might this have on the value of r?
Reduce r
To answer this question, refer to the following hypothetical data collected using replicated measures design: What is your conclusion regarding H0 using a = 0.052
Reject H0
For a linear relationship to exist, all the points must fall on a straight line.
False
For all problems, we must use either the Addition Rule or the Multiplication Rule, but not both.
False
The z score and the z distribution are the same thing.
False
To use a random number table properly one must begin on the top left hand column and read across.
False
Two events are considered mutually exclusive if the probability of one event does not influence the probability of a second event.
False
Type I errors are always worse to make than Type II errors.
False
If events are mutually exclusive they cannot be _________.
Independent
H0 and H1 must be mutually exclusive and exhaustive.
True
H1 and H0, taken together, cover the entire continuum with regard to possible effects of the independent variable.
True
If H0 is false, and we retain it, we have made a Type II error.
True
If H0 is true and we reject it, we have made a Type I error.
True
If H0 is true, beta equals 0.00.
True
If H1 is nondirectional one must evaluate the probability of getting the obtained result or a result more extreme in both directions to properly test H0.
True
If a = 0.01 and H1 is 2-tailed then there is 0.005 under each tail.
True
If a = 0.05 and chance alone is operating, it is reasonable to expect that on the average one would make one Type I error in every 20 experiments.
True
The area beyond a z score of -1.12 is the same as the area beyond a z score of 1.12.
True
The area under the normal curve represents the proportion of scores that are contained in the area.
True
A scatter plot _________.
Is a graph of paired X and Y values
Captain Kirk and Mr. Spock are engaged in a 3-D backgammon playoff, a game employing 6 dice. Kirk asks Spock the probability of rolling the dice and observing 6 sixes. Assume the dice are not biased. Spock's correct a priori reply is _________.
"One-sixth to the sixth power, Sir." Translation: (1/6)6
A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38. The stock price beyond which 0.05 of the distribution falls is _________.
$12.44
Given the following set of sample raw scores, X: 1, 3, 4, 6, 8. What is the z transformed value for the raw score of 3?
-0.52
A traffic safety officer conducted an experiment to determine whether there is a correlation between people's ages and driving speeds. Six individuals were randomly sampled and the following data were collected. The value of Pearson r equals ________.
-0.70
Which Pearson correlation coefficient shows the strongest relationship between two variables?
-0.80
Which of the following values of r represents the strongest degree of relationship between two variables?
-0.80
Y can be most accurately predicted from X if the correlation between X and Y is _________.
-0.98
The correlation coefficient between heights from the ground of two people on the opposite ends of a seesaw would be _________.
-1.0
Which of the following z scores represent(s) the most extreme value in a distribution of scores assuming they are normally distributed?
-3.12
If zX equals zY for each pair of points, r will equal _______.
1.00
An economics test was given and the following sample scores were recorded: The z score for individual D is __________.
0
E(z-uz) equals __________.
0
If A and B are mutually exclusive and exhaustive, then p(A and B) = _________.
0
The mean of the z distribution equals _________.
0
The z score corresponding to the mean of a raw score distribution equals _________.
0
Probabilities vary between _________.
0 and 1
A "hungry" undergraduate student was looking for a way of making some extra money. The student turned to a life of vice - gambling. To be a good gambler, he needed to know the probability of certain events. Help him out by answering the following question A royal flush in poker is when you end up with the ace, king, queen, jack, and 10 of the same suit. It's the most rare event in poker. If you are playing with a well- shuffled, legitimate deck of 52 cards, what is the probability that if you are dealt 5 cards, you will have a royal flush? Assume randomness.
0.000000013
Let's assume you are having a party and have stocked your refrigerator with beverages. You have 12 bottles of Coors beer, 24 bottles of Rainier beer, 24 bottles of Schlitz light beer, 12 bottles of Hamms beer, 2 bottles of Heineken dark beer and 6 bottles of Pepsi soda. You go to the refrigerator to get beverages for your friends. In answering the following question assume you are randomly sampling without replacement. What is the probability your first three bottles selected are Pepsi's?
0.00024
A "hungry" undergraduate student was looking for a way of making some extra money. The student turned to a life of vice - gambling. To be a good gambler, he needed to know the probability of certain events. Help him out by answering the following question. The probability of drawing an ace, a king and a queen of any suit in that order is _________. Sampling is without replacement from a deck of 52 ordinary playing cards.
0.00048
The probability of drawing an ace followed by a king (without replacement) equals _________.
0.0060
The probability of correctly guessing a two digit number is _________.
0.0100
To answer this question, refer to the following hypothetical data collected using replicated measures design: In a two-tailed test of H0 using a = 0.05, what is p(obtained) for the results shown?
0.0216
The standard deviation of the z distribution equals _________.
1 and the variance of the z distribution
If you have 15 red socks (individual, not pairs), 24 green socks, 17 blue socks, and 100 black socks, what is the probability you will reach in the drawer and randomly select a pair of green socks? (Assume sampling without replacement.)
0.0228
The probability of throwing two ones with a pair of dice equals _________.
0.0278
A "hungry" undergraduate student was looking for a way of making some extra money. The student turned to a life of vice - gambling. To be a good gambler, he needed to know the probability of certain events. Help him out by answering the following question. The probability of rolling "boxcars" (two sixes) with one roll of a pair of fair dice is _________.
0.028
Suppose you are going to randomly order individuals A, B, C, D, E and F. The probability the order will begin A B _ _ _ _ is _________.
0.033
If a town of 7000 people has 4000 females in it, then the probability of randomly selecting 6 females in six draws (with replacement) equals _________.
0.0348
Using the sign test, with N = 15 and a = 0.052-tail, if H0 is true, the probability of making a type I error equals _________.
0.0352
A psychologist is interested in whether hypnosis affects brain dominance. Twelve college students from the freshmen class are randomly sampled for an experiment. The experiment has two conditions which are given on different days. In condition 1, the students are hypnotized and then given a test which measures the relative dominance of the right and left hemispheres. The higher the score, the more dominant is the right hemisphere. In condition 2, the same students are given the test again, only this time they are not hypnotized but are in their normal state of consciousness. The following scores are obtained. The obtained probability = _________.
0.0384
A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed. The proportion of scores that lie above 650 is _________.
0.0475
A certain university maintains a colony of male mice for research purposes. The ages of the mice are normally distributed with a mean of 60 days and a standard deviation of 5.2. Assume you randomly sample one mouse from the colony. The probability his age will be greater than 68 is _________.
0.0618
The probability of correctly calling 4 tosses of an unbiased coin in a row equals _________.
0.0625
Assume you are rolling two fair dice once. The probability of obtaining a sum of 5 equals _________.
0.1111
A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed. The proportion of scores between 300 and 400 is _________.
0.1203
A "hungry" undergraduate student was looking for a way of making some extra money. The student turned to a life of vice - gambling. To be a good gambler, he needed to know the probability of certain events. Help him out by answering the following question. The probability of drawing a face card (king, queen or jack) of any suit from a deck of 52 ordinary playing cards in one draw is _________.
0.231
A researcher wanted to know if the order in which runners finish a race is correlated with their weight. She conducts an experiment and the data are given below. The correlation for these data equals _________.
0.31
If µ = 400 and s = 100 the probability of selecting at random a score less than or equal to 370 equals _________.
0.3821
A traffic safety officer conducted an experiment to determine whether there is a correlation between people's ages and driving speeds. Six individuals were randomly sampled and the following data were collected. The proportion of variability of Y accounted for by X is _________.
0.49
The proportion of scores less than z = 0.00 is _________.
0.50
What is the value of the Spearman rank order correlation coefficient (rho) for the following pairs of ranks?
0.50
A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed. The proportion of scores that lie between 460 and 600 is _________.
0.5365
If a stranger gives you a coin and you toss it 1,000,000 times and it lands on heads 600,000 times, what is p(Heads) for that coin?
0.6000
If µ = 35.2 and s = 10, then p(X) for X < 39 equals _________. Assume random sampling.
0.6480
The probability of rolling an even number or a one on a throw of a single die equals _________.
0.6667
A famous hypnotist performs in Meany Hall before a crowd of 350 students and 180 non-students. The hypnotist knows from previous experience that one-half of the students and two-thirds of the non-students are hypnotizable. What is the probability that a randomly chosen person from the audience will be hypnotizable or will be a non-student?
0.670
If 49% of the total variability of Y is accounted for by X, what is the value of r?
0.70
A certain university maintains a colony of male mice for research purposes. The ages of the mice are normally distributed with a mean of 60 days and a standard deviation of 5.2. Assume you randomly sample one mouse from the colony. The probability his age will be between 55 and 70 days is _________.
0.8041
What is the value of r for the following relationship between height and weight?
0.87
Let's assume you are having a party and have stocked your refrigerator with beverages. You have 12 bottles of Coors beer, 24 bottles of Rainier beer, 24 bottles of Schlitz light beer, 12 bottles of Hamms beer, 2 bottles of Heineken dark beer and 6 bottles of Pepsi soda. You go to the refrigerator to get beverages for your friends. In answering the following question assume you are randomly sampling without replacement. What is the probability the first beverage you get is a beer?
0.9250
An economics test was given and the following sample scores were recorded: The z score for individual G is _________.
1.42
An economics test was given and the following sample scores were recorded: The mean of the distribution is _________.
10.00
A standardized test has a mean of 88 and a standard deviation of 12. What is the score at the 90th percentile? Assume a normal distribution.
103.36
On a test with a population mean of 75 and standard deviation equal to 16, if the scores are normally distributed, what is the percentile rank of a score of 56?
11.70
A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38. The percentage of scores that lie between $9.00 and $10.00 is _________.
15.31%
What is the slope for the points X1 = 30, Y1 = 50 and X2 = 25 and Y2 = 40?
2.00
An economics test was given and the following sample scores were recorded: The standard deviation of the distribution is _________.
2.11
If the correlation between two variables is -1.00 and the score of a given individual is 2.20 standard deviations above the mean on one of the variables, we would predict a score on the second variable of _________.
2.20 standard deviations below the mean
On a test with a population mean of 75 and standard deviation equal to 16, if the scores are normally distributed, what percentage of scores fall between 70 and 80?
24.34
Assuming the z scores are normally distributed, what is the percentile rank of a z score of -0.47?
31.92
A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38. What percentage of the distribution lies below $7.42.
32.28%
For the following X and Y scores, how much of the variability of Y is accounted for by knowledge of X? Assume a linear relationship.
34%
If alpha equals 0.05, how many times out of 100 would you expect to reject the null hypothesis when the null hypothesis is in fact true?
5
A distribution has a mean of 60.0 and a standard deviation of 4.3. The raw score corresponding to a z score of -1.51 is _________.
53.5
If a population of scores is normally distributed, has a mean of 45 and a standard deviation of 6, the most extreme 5% of the scores lie beyond the score(s) of _________.
56.76 and 33.24
A distribution has a mean of 60.0 and a standard deviation of 4.3. The raw score corresponding to a z score of 0.00 is _________.
60.0
A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed. The raw score that lies at the 90th percentile is _________.
615.20
A distribution has a mean of 60.0 and a standard deviation of 4.3. The raw score corresponding to a z score of 2.02 is _________.
68.7
In a normal distribution approximately _________ of the scores will fall within 1 standard deviation of the mean.
70%
On a test with a population mean of 75 and standard deviation equal to 16, if the scores are normally distributed, what percentage of scores fall below a score of 83.8?
70.88
A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38. What percentage of the distribution lies between $5 and $11?
78.41%
Correlation implies causation.
False
If the odds in favor of an event occurring are 9 to 1, the probability of the event occurring is _________.
9/10
A testing bureau reports that the mean for the population of Graduate Record Exam (GRE) scores is 500 with a standard deviation of 90. The scores are normally distributed. The percentile rank of a score of 667 is _________.
96.86%
A stockbroker has kept a daily record of the value of a particular stock over the years and finds that prices of the stock form a normal distribution with a mean of $8.52 with a standard deviation of $2.38. The percentile rank of a price of $13.87 is _________.
98.78%
When deciding which measure of correlation to employ with a specific set of data, you should consider _________.
A an B
Which of the following is (are) not correct interpretations of Pearson r?
A and c
Which of the following is(are) correct interpretation(s) of correlation? Correlation _________.
A and c
A testing service has 1000 raw scores. It wants to transform the distribution so that the mean = 10 and the standard deviation = 1. To do so, _________.
A and d
In the equation Y = bX + a, X and Y, b is _________.
A constant and slope of the line
In the equation Y = bX + a, X and Y, a is _________.
A constant giving the value of the Y axis intercept
If we set alpha at 0.05 instead of 0.01, other factors held constant _________.
A lower risk of a Type I error and a lower risk of a Type II error
After several studies, Professor Smith concludes that there is a zero correlation between body weight and bad tempers. This means that _________.
A person with a bad temper may be heavy or skinny
A priori probability refers to _________.
A probability value deduced from reason alone
A posteriori probability refers to _________.
A probability value determined after collecting data
In an imperfect relationship, _________.
A relationship exists, but all of the points do not fall on the line
If you reject the null hypothesis, you may be making _________.
A type I error and a correct decision
If you retain the null hypothesis, you may be making _________.
A type II error and a correct decision
Events that occur only rarely have a probability equal to 0.00.
False
A sample is random if _________.
A, or a and b
A relationship can be _________.
All of these
In a normal distribution the z score for the mean equals _________.
All of these
It is important to know the possible errors (Type I or Type II) we might make when rejecting or retaining H0 _________.
All of these
The sign test can be used for _________.
All of these
Which of the following are examples of mutually exclusive events?
All of these
You have noticed that as people eat more ice cream they also have darker suntans. From this observation, you conclude _______.
All of these are possible
Pearson r is _______.
All of these are true
In a perfect relationship, _________.
All the points fall on the line
If a correlation is perfect,
All the points must fall on a straight or curved line
In a negative relationship, _________.
As X increases, Y decreases
In a positive relationship, _________.
As X increases, Y increases and as X decreases, Y decreases
In a negative relationship, _________.
B is negative
If P + Q = 1.00 then P and Q must be _________.
Both mutually exclusive and exhaustive
Correlation and regression differ in that _________.
Both of these are true
If p(A) = 0.6 and p(B) = 0.5, then p(B|A) equals _________.
Cannot be determined from the information given
When events A and B are mutually exclusive but not exhaustive, p(A or B) equals _________.
Cannot be determined from the information given
Which of the following statements is true?
Causation implies correlation
If you reject H0 when H0 is false, you have made a _________.
Correct decision
If p(A and B) = p(A)p(B|A) ¹ p(A)p(B), then A and B are _________.
Dependent
In the repeated measures design, _________.
Differences between paired scores are analyzed
In order for the correlation coefficient to be negative, which of the following must be true?
E XY<(EX)(EY)/N
A correlation coefficient expresses quantitatively the degree of relationship between two variables.
False
A priori and a posteriori probability have the same meaning.
False
A z distribution always is normally shaped.
False
An a posteriori approach to probability is never used because it is only an approximation of the true probability.
False
As the value of r increases, the proportion of variability of Y that is accounted for by X decreases.
False
Assuming a correlation exists, as the range of one of the variables decreases, r increases.
False
Given a -1.00 correlation coefficient, a raw score of 32 on one measure must be accompanied by a score of -32 on the corresponding second measure.
False
H0 always asserts that the dependent variable has no effect on the independent variable.
False
Hypothesis testing is part of inferential statistics while parameter estimation is used in descriptive statistics.
False
If A and B are independent then p(B|A) = p(A) or p(B).
False
If H0 is false and we reject it, we have made a Type II error.
False
If H0 is validly rejected, H1 must be true.
False
If a set of events is exhaustive, they only constitute a part of the possible events.
False
If one calculates r for a set of data and r equals 0.84, one can be certain that the relationship between the variables is not spurious.
False
If r = -1.00, the relationship is imperfect.
False
If results are statistically significant, the independent variable must have had a large effect.
False
If sampling is without replacement, the events are independent.
False
If the original raw score distribution has a mean that is not equal to zero, the mean of the z transformed scores will not equal zero either.
False
If the original raw score distribution is not normally distributed, the mean of the z transformation scores of the raw data will not equal 0.
False
If the relationship is imperfect, the value of the correlation coefficient must be negative.
False
If the value of r on ratio scaled raw data were 0.87 and the pairs of numbers were converted to ordinal data, and r calculated for the ordinal data, r would equal 0.87.
False
If we reject H0 then we are absolutely certain the independent variable affected the dependent variable.
False
In a plot of the normal curve, frequency is plotted on the X axis.
False
In a straight line the slope approaches zero as the line comes near the point X, Y.
False
In order to compute r, we must first convert each score to its z score and then do our calculations with the z scores.
False
In the standard normal curve, 13.59% of the scores will always be contained between the mean (µ) and +1s.
False
It is always appropriate to use a directional alternative hypothesis.
False
It is appropriate to determine if H1 is directional or nondirectional after the data is analyzed.
False
It is impossible to get 20 pluses out of 20 pairs of scores in a replicated measures design due to chance alone.
False
It is impossible to have a z score of 23.5.
False
It is impossible to have a z score of 30.2.
False
Probability values range from -1.00 to +1.00.
False
Retaining H0 and accepting H0 mean the same thing.
False
Rho is used where one or both variables are at least of interval scaling.
False
Since r is so widely used, it is appropriate to calculate r for nonlinear data.
False
The alternative hypothesis must be nondirectional.
False
The coefficient of determination equals pie r.
False
The easiest way to determine if a relationship is linear is to calculate the regression line.
False
The more stringent the alpha level is, the easier it is to detect an effect of the independent variable on the dependent variable.
False
The normal curve reaches the horizontal axis in 4 standard deviations above and below the mean.
False
The range of a correlation coefficient is 0 to +1.
False
The sign test analyzes both the magnitude and direction of the data.
False
The sign test analyzes raw scores.
False
The statement "Drug X has no effect on Y and any observed effect is due to chance alone" is an example of a nondirectional alternative hypothesis.
False
Unless the very same subject is used in the control and experimental condition the design cannot be a replicated measures design.
False
We always evaluate just the specific result obtained in the experiment.
False
When a sampled score is put back in the population before selecting the next score, this process is called sampling without replacement.
False
When two events are dependent, then p(A and B) = p(A) + p(B).
False
When two events are mutually exclusive then p(A and B) must equal 1.00.
False
p(B|A) is read probability of B divided by A.
False
r decreases as N decreases.
False
Knowing nothing more than that IQ and memory scores are correlated 0.84, you could validly conclude that _________.
Good memory causes high IQ
If the correlation between variables X and Y is 0.95, which of the following is true?
High scores of X are accompanied by high scores of Y
The closer the points on a scatter diagram fall to the regression line, the _________ between the scores.
Higher the correlation
A psychologist is interested in whether hypnosis affects brain dominance. Twelve college students from the freshmen class are randomly sampled for an experiment. The experiment has two conditions which are given on different days. In condition 1, the students are hypnotized and then given a test which measures the relative dominance of the right and left hemispheres. The higher the score, the more dominant is the right hemisphere. In condition 2, the same students are given the test again, only this time they are not hypnotized but are in their normal state of consciousness. The following scores are obtained. The nondirectional alternative hypothesis is _________.
Hypnosis affects brain dominance
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 statistics whiz, advises you to transform the raw scores to z scores; that the z scores will be normally distributed. You should _________.
Ignore the advice because z distributions have the same shape as the raw scores
When a correlation exists, lowering the range of either of the variables will _________.
Lower the correlation
If N is small, an extreme score _________.
Might have a large effect on robt
If p(A and B) = 0, then A and B must be _________.
Mutually exclusive
If p(A or B) = p(A) + p(B) then A and B must be _________.
Mutually exclusive
In stating H0 and H1, one must be certain that they are _________.
Mutually exclusive and exhaustive
If a distribution of raw scores is negatively skewed, transforming the raw scores into z scores will result in a _________ distribution.
Negatively skewed
In order to properly use rho, the variables must be of at least _______ scaling.
Ordinal
A correlation of r = 0.60 exists between a set of X and Y scores. If a constant of 10 is added to each score of both distributions, the value of r will _______.
Remain the same
To answer this question, refer to the following hypothetical data collected using replicated measures design: What would you conclude using a = 0.012 tail?
Retain H0
A researcher wanted to know if the order in which runners finish a race is correlated with their weight. She conducts an experiment and the data are given below. What is the appropriate correlation coefficient for these data?
Rho
If the results of an experiment allow rejection of the null hypothesis, _________.
Similar results are likely to occur if the experiment is repeated
You have just taken a standardized skills test designed to help you make a career choice. Your math skills score was 63 and your writing skills score was 45. The standardized math distribution is normally distributed, with m = 50, and s = 8. The writing skills score distribution is also normally distributed, with m = 30, and s = 10. Based on this information, as between pursuing a career that requires good math skills or one requiring good writing skills, you should chose _________.
The career requriring good math skills
When the results of an experiment are nonsignificant, the proper conclusion(s) is (are) _________.
The experiment fails to show a real effect for the independent variable
A psychologist is interested in whether hypnosis affects brain dominance. Twelve college students from the freshmen class are randomly sampled for an experiment. The experiment has two conditions which are given on different days. In condition 1, the students are hypnotized and then given a test which measures the relative dominance of the right and left hemispheres. The higher the score, the more dominant is the right hemisphere. In condition 2, the same students are given the test again, only this time they are not hypnotized but are in their normal state of consciousness. The following scores are obtained. The population to which these results apply is _________.
The freshman class
For dependent events, p(A and B) = p(A)p(B|A).
True
The null hypothesis which is appropriate for a directional alternative hypothesis asserts that _________.
The independent variable does not have an effect in the direction predicted by H1
When the results are statistically significant, this means _________.
The obtained probability is equal to or less than alpha and we can reject H0
lf alpha is changed from 0.05 to 0.01, _________.
The probability we will retain a false H0 increases
Which of the following statements concerning Pearson r is not true?
The relationship between the two variables must be nonlinear
If a relationship is linear, _________.
The relationship can be most accurately represented by a straight line
In an experiment with a repeated measures design _________.
The same subjects recieve both treatments
lf we drew a random sample from an introductory psychology class, to whom could we generalize our results?
The students in that introductory psychology class
Table A in your textbook has no negative z values, this means _________.
The table can be used with both positive and negative z values because it is symmetrical
Which of the following is (are) not correlation coefficients?
They all are correlation coefficients
Two events are mutually exclusive if _________.
They both cannot occur together
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 _________.
They should hire a new statistician
A random sample results when each possible sample of a given size has an equal chance of being selected.
True
A raw score that is 1 standard deviation above the mean of the raw score distribution will have a z score of 1.
True
A replicated measures design is the same thing as a correlated groups design.
True
A scatter plot is used to help determine if the relationship is linear or curvilinear.
True
A z score designates how many standard deviations the raw score is above or below the mean.
True
A z transformation will allow comparisons to be made when units of distributions are different.
True
Beta is the probability of retaining H0 when H0 is false.
True
By making alpha smaller we can decrease the probability of making a Type I error.
True
Causation implies correlation.
True
Correlation deals with the relationship between two variables.
True
For a sample to be random, all the members must have an equal chance of being selected into the sample.
True
For any z distribution of normally distributed scores, P50 is always equal to zero.
True
If alpha is made more stringent, beta increases.
True
If an event is certain not to occur, its probability of occurrence equals 0.00.
True
If scores are z scores and if r equals 1 then zX will always equal zY.
True
If the probability of the results obtained equals 0.05 and a = 0.05, you should reject H0.
True
If two events are mutually exclusive and exhaustive, P + Q = 1.
True
If two events are mutually exclusive, they must be dependent.
True
If we reject H0 one can say the experimental results are significant.
True
In a normal curve, the area contained between the mean and a score that is 2.30 standard deviations above the mean is 0.4893 of the total area.
True
In a perfect linear relationship all the points must fall on a straight line.
True
In a perfect positive correlation, each individual obtains the same z score on each variable.
True
In an inverse relationship as one variable gets larger the other variable gets smaller.
True
In hypothesis testing it is incorrect to evaluate the probability of the specific outcome of the experiment.
True
In order to generalize to the population a sample must be randomly selected.
True
In the real world the scientist can never be certain whether or not H0 is true.
True
It is impossible to prove with certainty the truth of H1 when using sample data
True
It is not possible to analyze the probability of the alternative hypothesis because the laws of probability are derived for chance events. This is why we test H0 instead of H1.
True
It is permissible to use a directional H1 when there are good theoretical as well as strong supporting data to justify the predicted direction.
True
One reason for calculating r from z scores is to make r independent of units and scaling.
True
Pearson r requires that the data be of interval or ratio scaling.
True
Probability values range from 0 to 1.
True
Regardless of whether H1 is directional or nondirectional, when evaluating H0 we always assume chance is responsible for the differences in results between conditions.
True
Restricting the range of either X or Y will generally lower the correlation between the variables.
True
Sampling without replacement is usually used in choosing subjects for an independent groups design experiment.
True
The Addition Rule concerns one of several possible events.
True
The Multiplication Rule concerns the joint or successive occurrence of several events.
True
The addition and multiplication rules can apply to any number of events.
True
The addition rule is concerned with determining the probability of A or B, while the multiplication rule is concerned with determining the probability A and B.
True
The area beyond a z score of +2.58 is 0.005.
True
The coefficient of determination equals the proportion of variability accounted for by the relationship between the variables.
True
The correlation between two variables when N = 2 will always be perfect.
True
The correlation coefficient r is a descriptive statistic.
True
The correlation coefficient when N = 2 is meaningless.
True
The critical probability for rejecting H0 is the alpha level.
True
The farther away the points on a scatter diagram fall from the regression line, the lower the correlation.
True
The formula for rho is actually just the formula for Pearson's r simplified to apply to lower order scaling.
True
The normal curve is a symmetric, bell-shaped curve.
True
The normal curve never touches the X axis.
True
The sign test ignores the magnitude of the difference scores.
True
The slope of a line is a measure of its rate of change.
True
The slope of the line reveals whether the relationship is positive or negative.
True
The standard deviation of the z distribution is always equal to 1.0.
True
The use of z scores allows comparisons between variables measured on different scales and units.
True
The value of r obtained by calculating the correlation between X and Y is the same as the correlation between Y and X.
True
The value used for alpha depends on the consequences of making a Type I and Type II error.
True
The z distribution takes on the same shape as the raw scores.
True
Two events are independent if the occurrence of one has no effect on the probability of occurrence of the other.
True
We always evaluate the tail of the distribution, beginning with the obtained result, rather than just the obtained result itself.
True
When a variable is continuous, p(A) equals the area under the curve corresponding to A divided by the total area under the curve.
True
It is possible to compute a coefficient of correlation if one is given _________.
Two sets of measurements on the same individuals
If you reject the null hypothesis, what type of error might you be making?
Type I
If alpha is 0.05 and obtained probability level is 0.01, you could be making a _________.
Type I error or a correct decision
In the equation Y = bX + a, X and Y are _________.
Variables
If we set alpha at 0.05 instead of 0.01 _________.
We have a greater risk of a Type I error and we have a lesser risk of a Type II error
Rho is used _________.
When one or both variables are only of ordinal scaling
Would you rather have an income (assume a normal distribution and you are greedy) _________.
With a z score 1.96
If you transformed a set of raw scores, and then added 15 to each z score, the resulting scores _________.
Would have a standard deviation =1 and a mean of =15
In a positive relationship, _________.
b is positive
The Multiplication Rule states _________.
p(A and B) = p(A)p(B|A)
The Addition Rule states _________.
p(A or B) = p(A) + p(B) - p(A and B)
If events A and B are independent, then p(A and B) = _________.
p(A)p(B)
You have conducted a brilliant study which correlates IQ score with income and find a value of r = 0.75. At the end of the study you find out all the IQ scores were scored 10 points too high. What will the value of r be with the corrected data?
r will remain the same
The proportion of variance accounted for by a correlation between two variables is determined by _________.
r2
A psychologist is interested in whether hypnosis affects brain dominance. Twelve college students from the freshmen class are randomly sampled for an experiment. The experiment has two conditions which are given on different days. In condition 1, the students are hypnotized and then given a test which measures the relative dominance of the right and left hemispheres. The higher the score, the more dominant is the right hemisphere. In condition 2, the same students are given the test again, only this time they are not hypnotized but are in their normal state of consciousness. The following scores are obtained. Using a= 0.05 2 tail, your conclusion is ___________.
reject H0; hypnosis affects brain dominance
Two events are independent if _________.
the occurrence of one has no effect on the probability of occurrence of the other