Statistics Chapter 1, Chapter 2, Ch 3, Chapter 6, Chapter 5

What is wrong in the following table? Score f 20 4 19 6 18 2 15 1 10 8

* relative freq are reported in the f column?

The mean is the preferred measure of central tendency when

* the scale of measurement is ordinal, interval, or ratio, and the distribution is skewed.

The median is the appropriate measure of central tendency when

* the scores are ordinal, or when the distribution is skewed and the scores are interval or ratio.

Which of the following distributions are unimodal?

*1, 1.1, .1, 11, .11

A researcher records 52 scores. What is the median position of these scores?

*27th score in numeric order

What is the mean for the following set of scores: 19, 1, 1, 2, 2?

*5

A study about the college aptitude of seniors at North City High School has resulted in a sample mean with a corresponding z-score of −2.00. If the critical value for the region of rejection is what is the correct conclusion?

*Since the z-value does not fall within the region of rejection, we should conclude this sample mean likely represents some other population.

What is the critical value?

*The outer end of the region of rejection

When does sampling error occur?

*When a sample statistic is not equal to the population parameter as a result of chance factors

The population mean is estimated by

*calculating the mean of a sample and then transforming it to reflect the size of the population

When we refer to a score's deviation, we are referring to

*how far it is from other scores.

The best predictor of an individual score in a sample of scores is the

*mean of the sample of scores.

When we graph the results of an experiment, the Y axis indicates the

*measure of central tendency we have used fro the dependent variable.

When a z-score is not in the region of rejection, we should

*reject the idea that random chance produced a sample representing the population poorly.

Error refers to expected errors in predicting unknown scores and is represented by

*the deviation of a score from the mean.

When we graph results from an experiment, a line graph is appropriate when

*the independent variable is interval or ratio

A researcher records the following data for the number of different food items chosen by seven participants in a buffet-style setting: 1, 6, 2, 5, 4, 3, and 7. Is the mean equal to the median in this example?

*there is not enough information to answer the question

When a very skewed distribution is involved,

*use the median because it is more representative of most of the scores.

Suzy is about to pick a cookie from a cookie jar. The cookie jar contains 4 chocolate chip, 3 vanilla, 2 ginger snap, and 1 sugar cookie. What is the probability that Suzy will not pick a vanilla cookie?

.7

Which of the following best describes knowing the relative frequency of every possible event in a population?

a probability distribution

A statistics class has 60% females and 40% males. A researcher selects a sample having 80% males and 20% females. Why should the researcher be cautious of making inferences about the entire class based on the sample?

because the sample appears to be unrepresentative of the population

How is the relative frequency of an event defined?

c. the proportion of times an event occurs in the population of events

The variable systematically changed or manipulated by a researcher in an experiment is called the

independent variable

In order to make statements about the population from information obtained from a sample, we must use

inferential statistics.

z-scores can be calculated from

interval or ratio scores

What are the shaded areas in the following distribution called?

tails

Sx and S2x and are considered biased estimates for the population standard deviation and variance because

they reflect the variability of only N-1 scores

The distribution of z-scores is always

the same shape as the distribution of raw scores.

In order to decide which measure of central tendency is appropriate, you must first determine

the scale of measurement being used and the shape of the distribution.

A program evaluator for a large school district wants to know how much intelligence varies in the elementary schools. She 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?

the standard deviation

Another term for the standard deviation of the sampling distribution of means is known as

the standard error of the mean.

Suppose you are interested in how participants perform under different temperature conditions. You select 30 participants and assign them to work in one of three rooms. The rooms differ only with respect to temperature. You instruct all participants to solve the same jigsaw puzzle, and then you measure how long it takes each one to finish. In this research, the experimenter is investigating whether

the time required to solve a jigsaw puzzle depends on temperature.

In general, the larger the value of the standard deviation,

the wider the distribution

A grouped frequency distribution is used when

there are too many different scores to produce an efficient frequency table or graph.

Why shouldn't the mode be used with the following set of scores? 2, 5, 3, 3, 4, 2, 4, 5, 1, 1

there is no mode

Adding numbers is an important procedure in statistics. Instead of saying "add up all of the scores," we use the symbol

Σ.

Variance is defined as the

average of the squared deviations around the mean.

A researcher asks participants to estimate the height (in inches) of a statue that was in a waiting area. The researcher records the following estimates: 40, 46, 30, 50, and 34. If the researcher removes the estimate of 40 (say, due to an experimenter error), then the value of the mean will ______

*

A researcher records the time (in seconds) that participants arrive late for a scheduled research study. Assuming these data are normally distributed, which measure of central tendency is most appropriate to describe these data?

* mean

Sally's z-score on a given measure is -2.5, where the population mean is 5 and the standard deviation is 1.5. What is Sally's raw score?

1.25

What is the most frequently occurring score in the following frequency distribution? Score f 15 1 14 2 13 3 12 4 11 5

11 (score that has the highest frequency number)

Suppose you received a 95 on an exam where the mean score was 83. What is your score's deviation?

12

Using the frequency distribution below, what is the total frequency of the scores 6 and 7?

15

What is the N for the following frequency distribution? Score f 15 1 14 2 13 3 12 4 11 5

15

Suppose the population mean of some measure is 6 and the population standard deviation is 12. For a sample of 36, what is the standard error of the mean?

2

What is the relative frequency for the score of 14 in the following simple frequency distribution? Score f 15 1 14 2 13 3 12 4 11 5

2/ 15= 0.13

If a score appears 20 times in a sample of 80 scores, what is its relative frequency?

20/ 80=* .25? or 80/20= 4?

What is the percent for the score 7 in the following distribution

22

What is the ΣX for the scores of 5, 1, 5, 2, and 10?

23

If a score's relative frequency is .6 when N is 50, what is the score's frequency?

30

In a normal distribution, approximately what percentage of scores is not between -1 Sx and Sx

32%

Consistent with the basic premise of a representative sample, if a given population consists of 60% women, your sample should have

40% men

In a normal distribution with a mean of 30, what percentage of the scores would be above the mean?

50%

A researcher records the following scores: 5, 3, 7, 6, 2, 8, 0, and 1. In terms of these data, the sum of the squared differences of scores from their mean is ______.

60

Suppose you have a set of normally distribution data where the mean is 120 and the standard deviation is 15. What score is located at -3 Sx?

75

Which of the following sets of data appears to show the greatest amount of variability?

99, 110, 153, 98, 64

When rolling a pair of fair dice, the probability of rolling a total point value of "7" is 0.17. If you rolled a pair of dice 1,000 times and the point value of "7" appeared 723 times, what would you probably conclude?

Although not impossible, this outcome is so unlikely the fairness of these dice is questionable.

A researcher investigates whether there is a relationship between hours of sleep and memory for photographs by having 40 people sleep in the laboratory and waking 20 of the participants after 4 hours of sleep and the others after 8 hours of sleep. After they are awakened, each participant is asked to study 21 photographs and then recall as many details from the photographs as possible. In this study, what is 8 hours of sleep?

A condition of the independent variable

Which of the following accurately describes a theoretical probability distribution?

A theoretical model based on how we assume nature distributes events in the population

Which of the following statements about bar graphs is false?

Adjacent bars touch.

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?

Calculate a z-score for each test.

For any approximately normal distribution, how can we find the relative frequency of the scores?

Convert the raw scores to z-scores and then use the standard normal curve.

An experimenter investigated the ability to concentrate under different conditions 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?

Find the mean amount of time it took to solve the puzzle, if time scores are normally distributed.

Symbols associated with different parameters come from the ....alphabet

Greek

Which graphing techniques are appropriate for interval and ratio data?

Histograms and frequency polygons

Which of the following is not a purpose of statistical procedures?

Hypothesizing data

When two normal z-distributions are plotted on the same graph, what can we say about the relative frequency of each z-score?

It will always be the same.

___________________ distributions contain low-frequency, extreme low scores without low-frequency extreme high scores.

Negatively skewed

A researcher records the following data for the number of complaints filed (per day) following a controversial policy change at a local business: 3, 8, 5, 0, 4, 6, 2, 1, 1, 4, 2, and 0. Is the mean equal to the median in this example?

No, mean is larger than median Mean= 3 *Median= 2.5

Suppose you flip a fair coin five times and get a "heads" each time. Your friend insists that your next flip certainly will come up as "tails." Is your friend correct?

No, though the gambler's fallacy makes us think this, it is not a guarantee that the next flip will be "tails."

A researcher records the following data for the number of times an interviewer is interrupted during a series of interviews: 0, 0, 3, 2, 5, 3, 0, 8, 0, 2, 1, and 1. Is the mode equal to the median in this example?

No; the median is larger than the mode.

A researcher records the following data for the time (in seconds) it takes five rats to cross an electrical grid to obtain reinforcement on the other side: 12, 9, 13, 4, and 12. Is the mean equal to the mode in this example?

No; the mode is larger than the mean.

To measure attraction, a researcher records the following data for the distance (in inches) between two persons sitting in a waiting room: 46, 32, 10, 23, 18, 46, and 60. Is the mode equal to the median in this example?

No; the mode is larger than the median.

Pat's last statistics test score was 72. If the instructor tells Pat the grade distribution was approximately normal, the class mean was 67, and the standard deviation was 3, which of the following is correct?

Pat should be fairly happy about this score, because many students did not do as well

___________________ distributions contain low-frequency, extreme high scores without low-frequency extreme low scores.

Positively skewed

________________________ tries to ensure that every member of a given population has an equal chance of inclusion in a given study.

Random selection

Of the following data sets, which shows a relationship?

Sample A x Y 1 10 1 11 2 15 2 16 3 20 3 21

A study about the college aptitude of seniors at South City High School has resulted in a sample mean with a corresponding z-score of +1.89. If the critical value for the region of rejection is +/- 1.96 what is the correct conclusion?

Since the z-score does not fall within the region of rejection, we should not conclude this sample mean represents some other population

Which of the following studies shows the strongest relationship between the independent and dependent variables?

Study D Condition 1 6 Condition 2 25 Condition 3 52

Which of the following statements accurately describes the sampling distribution of means?

The distribution of all possible sample means when an infinite number of samples of the same size N are selected from one raw score population.

What is the critical value?

The inner edge of the region of rejection

Suppose we compute and find it is equal to 5.5. How do we interpret this number?

The numbers in the sample deviate, on the average, 5.5 units from the mean.

How is the relative frequency of an event defined?

The proportion of times an event occurs in the population of events

What can we conclude when the absolute value of a z-score for a sample mean is larger than the critical value?

The sample mean does not represent the particular raw score population on which the sampling distribution is based.

What can you conclude about a sample mean falling within the region of rejection?

The sample probably represents some population other than the one on which the sampling distribution was based.

A program evaluator for a large school district wants to know how much intelligence varies in the elementary schools. She 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?

The standard deviation

What is wrong with the following formula

The symbol S^2 x indicates the sample variance, but the formula indicates the sample standard deviation.

Chris wants to calculate a z-score for his own height. The average height in the class is 66 inches, and Chris's height is 62 inches. Chris calculated his z-score to be +1.5. What's wrong with his calculation?

The z-score should be a negative number.

What do the design of the study and the scale of measurement have in common

They are the aspects of a study to consider when deciding which descriptive or inferential statistics to use

Which of the following is correct regarding means falling within the region of rejection when the critical values are +/- 1.96

They occur with a probability of 5%.

When computing the variance, why do we square the deviations from the mean?

To compensate for the fact deviations about the mean always sum to zero

What is the purpose of the critical value?

To define the minimum absolute z-value required for a sample to be in the region of rejection.

What is the essence of all inferential statistics?

Using sample data to make statements about the scores and relationships in the population

Which of the following is not one of the things the relative frequency of z-scores allows us to calculate for corresponding raw scores?

Values in terms of goodness or badness

When does sampling error occur?

When a sample statistic is not equal to the population parameter as a result of chance factors

You should first transform X to z in all of the following cases except if you seek

X that marks a given relative frequency beyond X in tail.

If we know the sample variance, can we use that information to find the sample standard deviation?

Yes, simply take the square root of the variance to find the standard deviation.

The variance can never be

a negative number

A dependent variable is so named because it is dependent on

a participant's reaction to a condition.

A cognitive psychologist found the mean recall of information increased consistently as the extent to which the participants elaborated on the material (none, minimal, extensive) changed. Also, the standard deviation for each condition was small. What does this suggest about the relationship between the amount of elaboration and recall?

a strong relationship exists

In statistics a sample is

a subset of a group to which a law is applied

The relative frequency of a score must be

a value between 0 and 1.

To obtain the mean, we would

add all the scores and divide by the total number of scores.

Which of the following statements about bar graphs is false?

adjacent bars touch

What do (S^2x), (s^2x), and (o^2x) have in common

all forms of variance

A staff member records the number of victories (per 10-game season) for a new football coach during his first three seasons with a team. The coach won 1, 3, and 8 games, respectively, over the three seasons. Which conclusion is appropriate?

all of these

the sum of the deviations around the mean

always equals zero

Quantitative variables particularly measure

amounts

Suppose you are interested in how participants perform under different temperature conditions. You select 30 participants and assign them to work in one of three rooms. The rooms differ only with respect to temperature. You instruct all participants to solve the same jigsaw puzzle, and then you measure how long it takes each one to finish. This research is an example of

an experimental study.

We can use the standard normal curve as our model for

any approximately normal distribution, when transformed to z-scores.

Sampling distributions of means are always

approximately normally distributed.

If the variance for a sample is computed and it is found to be rather large, the scores

are spread out around the mean

With respect to other scores in a distribution, measures of central tendency

are the points around which most of the scores are located.

Standard deviation is defined as the square root of the

average of the squared deviations around the mean.

Which of the following is not a step when deciding whether or not a population is being represented?

compute the mode

A specific amount or category of the independent variable creating the specific situation under which the participants' scores on some other variable are measured is called a/an

condition.

The term variability is most opposite to

consistency

If a sample has a small standard deviation, we can say the scores in the sample are

consistent

In a/an ______________________, the experimenter measures scores on two variables. In a/an ______________________, the experimenter manipulates or changes one variable and measures scores on the other.

correlational study; experiment

Another term for a "dot" placed on any graph is called a

data point

The variable measured as an experiment is being carried out is called the

dependent variable.

If I want to summarize the characteristics of my statistics class to my friend, I should use

descriptive statistics.

Correlational studies primarily are done to

determine whether there is a relationship between two variables

A z-score communicates a raw score's

distance from the mean in standard deviation

A z-score communicates a raw score's

distance from the mean in standard deviations.

To obtain the relative frequency, we would

divide the frequency for a score by the total number of scores.

In a z-distribution, the standard deviation will always be

equal to 1

In a z-distribution, the standard deviation will always be

equal to 1.

The mean of the sampling distribution of means is always

equal to the population mean.

In sampling distributions, all the samples contain sets of raw scores

from the same population

In sampling distributions, all the samples contain sets of raw scores

from the same population.

A deviation is more informative than a raw score because it

gives the score's location relative to the mean.

A representative sample is one

having characteristics accurately reflecting the characteristics of the population

Which of the following is a variable

height of the players on a basketball team

When we are considering measures of variability, we are effectively considering

how spread out a distribution is

Which of the following is not a purpose of statistical procedures?

hypothesizing data

The very first step when examining data is to

identify the shape of the distribution

Given a normal distribution, as z-scores' absolute values increase, those z-scores and the raw scores that correspond to them occur

less frequently

The greater the variability, the more spread out the scores are around the

mean.

The mean is used most often in behavioral research because researchers tend to

measure variables that have interval or ratio scores, and the scores form approximately normal distributions.

As with measures of centrality, the selection of a measure of variability should be based on

measurement scale and the shape of the distribution

The range of probabilities

must be between 0 and 1.

The mean tends to be lower than the median for ___________________________ distribution(s).

negatively skewed

Variables that are more appropriate to categorize tend to fall on the ________________________ scale.

nominal

Which of the following orders lists the scales of measurement from the scale providing the least specific information to the scale providing the most specific information?

nominal, ordinal, interval, ratio

In statistics, a symmetrical, bell-shaped polygon is called a/an

normal curve

The central limit theorem is particularly helpful in terms of understanding the basic nature of

normal distributions

The central limit theorem is particularly helpful in terms of understanding the basic nature of

normal distributions.

In statistical notation, f stands for the

number of times a given score occurs in a sample.

Your relative standing informs you

of how your scores compares with the sample or population from which it is derived

Your relative standing informs you

of how your scores compares with the sample or population from which it is derived.

In which type of distribution will the lowest scores be found on the lower left-hand side of the X axis?

only in a negatively skewed distribution

The individuals measured in a sample are called the

participants

µ is the symbol for the

population mean

When you see the symbol "p," it refers to

probability

Relative frequency is defined as the

proportion of the total N at a given score value

Gender is a clear example of a/an ... variable

qualitative

What do we call the portion of the sampling distribution in which values are considered too unlikely to have occurred by chance?

region of rejection

when a change in the scores of the one variable is accompanied by a consistent change in the scores of another variable, we have what is known as a

relationship

Which of the following studies is best for showing the first variable produces a change in the second variable

researcher has participants sleep various amounts of hours and then observes how cranky they are

Which of the following is not true of the criterion?

samples meeting the criterion occur more than 5% of the time

One benefit to using a frequency distribution table or graph is it makes it easier to

see a relationship hidden in the data

If you see the notation sum x2 you should

square all the Xs then sum the squares

numbers obtained from a sample are known as

statistics

Numbers obtained from a sample are known as

statistics.

To determine the range, we simply

subtract the highest score minus the lowest score

If you see the notation (sum X)^2 , you should

sum all the Xs then square the sum

Measures of variability are used to

summarize and describe the extent to which scores in a distribution differ from one another.

measure of variability are used to

summarize and describe the extent to which scores in a distribution differ from one another.

When the mean is used to predict scores, a deviation (X-mean) indicates

the difference between the mean we predict and the score an individual actually gets.

In statistics a population is

the entire group to which a law of nature applies

A psychology professor wanted to describe the adolescents in her state in terms of the personality characteristic of introversion/ extroversion. She selects a sample and measures their scores on a test of introversion/extroversion. The measure of variability she should calculate is

the estimated population standard deviation, because she wants to make inferences about the population based on her sample

The distinguishing characteristic of the frequency polygon is

the graph is created by connecting the dots with straight lines

What is the critical value?

the inner edge of the region of rejection

The greater the variability in a set of scores,

the less accurately the scores are represented by one central score.

The mean is defined as

the mathematical center of the distribution.

A program evaluator for a large school district wants to know how much intelligence varies in the elementary schools. She selects one classroom at each grade level in each elementary school and administers an intelligence test to the children in those classrooms. If the program evaluator wants to find out which school has the highest intelligence level, which of the following should she calculate for each school?

the mean

Which of the following is not viewed as a measure of variability?

the mean

The mode is defined as

the most frequently occurring score.

The median is defined as

the point at or below which 50% of the scores fall.

An event's relative frequency in the population equals

the probability of the event.

A z-score of zero always means

the raw score is equal to the mean

A z-score of zero always means

the raw score is equal to the mean.

When +1.645 is used as the critical value instead of ±1.96 and the criterion probability is 0.05 in both cases,

the region of rejection is all placed in the positive z-distribution tail.

In a normal curve, the proportion of the area under the curve between two scores represents

the relative frequency of all scores between the two scores.

The distribution of z-scores is always

the same shape as the distribution of raw scores

In statistical notation, N stands for the

total number of scores in a data set

A bimodal distribution will have ___________________________ mode

two

The distinguishing characteristic of an idealized bimodal distribution is

two scores have the same and the highest freq

in research, the aspects of the situation or behavior we measure are called

variables

In research, the aspects of the situation or behavior we measure are called

variables.

A relationship is not present when

virtually the same set of Y scores is paired with every X score.

With respect to a graph of a frequency distribution, a positive deviation score

will be located to the right of the mean.

A graph of a frequency distribution shows the frequencies on the

y axis