Statistics for the Behavior Sciences Midterm

A set of scores ranges from a high of x= 18 to a low of x= 5. If these scores were put in a grouped frequency distribution table with an interval width of 2 points, which of the following would be the top interval in the table?

18-19

The number of pizza slices eaten in the last month is 0. The frequency is 1. The number of participants in the study is 46. What is the % chance?

2.2

For the following frequency distribution of quiz scores, how many individuals took the quiz? X f 5 6 4 5 3 5 2 3 1 2

21

The first quartile (Q1) = percentile rank of ______?

25

If 2 standard deviations correspond to a 6-point distance, then 1 standard deviation must equal _____ points?

3 points

In a grouped frequency distribution table, one interval is listed as 35-39. If the scores represent a continuous variable, what are the real limits for this interval?

34.5 and 39.5

What is the sum of squares (SS) for the following scores? Scores 0, 6, 6, 8. N = 4. The mean is 5.

36

If n=20, what is k or the appropriate number of groups?

5

If the proportion of 0.05, what is the percentage?

5%

If your p is 5, what is your percent chance? Hint: think of the % chance formula.

500

Which statement below must be false regarding a distribution of scores?

75% of the scores are above the median

What is the range for the following set of scores? Scores: 5, 8, 7, 9, 2, 10

8 points

What is the variance of the population when SS = 36, and N = 4?

9

Find the X value corresponding to z= 0.75. The mean is 90 and the standard deviation is 4.

93

Which of the following is a requirement for a random sample?

All of these are correct - the probabilities cannot change during a series of selections - there must be a sampling with replacement - every individual has an equal chance of being selected

A large z indicates....

An extreme score?

The mean is the.....

Average score

For the population would a score of x= 85 be considered a central score (near the middle of the distribution) or an extreme score (far out in the tail of the distribution)? Mean = 75, standard deviation = 15.

Average score?

Which of the following actions will always change the value of the mean?

Changing the value of one score

If the variability is very low, most scores will cluster by the ________ score.

Mean

The numerical value of the z-score specifies the distance from the _______.

Mean

A distribution of scores is positively skewed. Which is the most probable order, from smallest to largest, for the three measures of central tendency?

Mode, Median, Mean

A (+) value times a negative (-) value equals a ________ value.

Negative

Different academic majors such as biology, psychology, and English are called _________.

Nominal

The primary advantage of the mode is that it can be used to measure and describe central tendency for data that are measured on a ________ scale.

Nominal

The p equals the f (frequency) or the number of a specific outcome, divided by the _________.

Number of possible outcomes.

Barbara is a psychologist who measures relationship satisfaction among couples by observing non-verbal behavior (e.g., smiling, mimicking partner actions). In this example, non-verbal behavior is an example of a(n) _____.

Operational definition

The participants in a research study self-report their sleep quality levels of choosing the response option that best characterizes their average sleep quality per night from the following response options: 1 = extremely low sleep quality, 2 = very low sleep quality, 3 = low sleep quality, 4 = extremely high sleep quality. Which measurement scale is being used to classify sleep quality?

Ordinal

______ is a value that describes the population.

Parameter

A researcher uses an anonymous survey to investigate the television-viewing habits of 100 American adolescents. The researcher plans to make an inference about the television-viewing habits of all American adolescents based on the results of the survey. The entire group of American adolescents is an example of a _____.

Population

What kind of formula is this? z= x-u/o

Population

The students in a psychology class seem to think that the midterm exam was very difficult. If they are correct, what is the most likely shape for the distribution of exam scores?

Positively skewed

Which statement accurately describes the proportions in the tails of a normal distribution?

Proportions in both the left-hand and right-hand tails tend to be relatively small.

For a research study examining how participant gender influences support for equality in society, participant gender is an example of which kind of variable?

Quasi-independent variable

What scale of measurement is being used when a researcher measures the amount of car accidents that participants have been involved in during their lifetime?

Ratio

A researcher uses an anonymous survey to investigate the social media habits of American college students. Based on the set of 300 surveys that were completed and returned, the researcher finds that students spend an average of 2 hours each day using social media. The set of 300 students who returned surveys is an example of ___________.

Sample

What kind of formula is this? z = X-M/s

Sample

The average verbal SAT score for the entire class of incoming college freshmen in the United States is 530. However, if a sample of 20 incoming college freshmen is randomly selected from the United States, it is likely that this sample's average verbal SAT score will not be exactly 530. This is consistent with the concept of _____.

Sampling Error

Which of the following accurately describes a hypothesis test?

a statistical technique that uses the data from a sample to evaluate a hypothesis about a population. Must be testable.

What is the more extreme alpha level?

.01

The number of pizza slices eaten in the last month is 0. The frequency is 1. The number of participants in the study is 46. What is the proportion of probability?

.022

What is the probability of randomly selecting a female from the population of psychology 2280 students (11 males, 27 females)? Hint: what is the p formula?

.711

Which proportion of a normal distribution is located in the tail above z = +1.50?

0.0668

If f is 2 and n is 20, what is p (I.e., the proportion)? Use the proportion equation to solve this problem?

0.10

Which proportion of a normal distribution is located in the tail below z = -1.00?

0.1587

Bags of skittles candies include six different colors: red, orange, yellow, green, blue, and purple. If the bag has an equal number of the six colors, what is the probability of selecting a green candy?

0.17

Calculate the mean for the random sample of psychology students, 3, 2, 2, 2, 2, 1, 1, 1. n = 8 The sum of x = 14

1.75

Find the group width? Largest x= 53, Smallest x= 16, k= 5

10

What is the median for the following set of scores? Scores: 1, 5, 11, 12, 20

11

What is the value of SS (sum of squared deviation) for the following population: 1, 1, 1, 5. The mean is 2.

12

What is the median? 1, 3, 9, 13, 15, 17, 19

13

What is the total number of scores for the distribution shown in the following table? X f 4 7 3 5 2 4 1 2

18

A class consists of 10 male students and 30 female students. If one student is randomly selected from the class, what is the probability of selecting a male student?

p = 10/40

What is the probability of selecting an individual with a score greater than x= 7 based on the histogram below?

p = 4/10

What is the mean for the population of scores presented in the frequency distribution table below? X f 8 3 7 3 6 0 5 2 4 1 3 2 2 2 1 3

u= 4.50

Which z-score corresponds to a score that is above the mean by 2 standard deviations?

+2

For a population with u = 84 and o = 4, which is the z-score corresponding to X= 80?

-1.00

Which statement below is consistent with computing a weighted average of two individual samples?

A computer weighted average will be closer to the mean average of the larger sample than the mean average of the smaller sample.

A relationship between study time and GPA is an example of?

A correlation

Z-scores are useful with regard to inferential statistics primarily because they offer a tool by which to determine whether _______.

A distribution of scores is standardized.

A researcher collects a sample of n=20 introductory psychology textbooks and records the number of pages in each book. The results are then placed in a grouped frequency distribution table using intervals of 0-99 pages, 100-199 pages, 200-299 pages, and so on. If the results were converted into a frequency distribution graph, which kind of graph(s) would be appropriate?

A histogram or polygon

A researcher surveys a sample of n=10 adults and asks them to indicate their favorite day of the week. If the data were organized in a frequency distribution table, what would be included in the first column?

A list of days of the week

Bars that do not touch on the x axis. Used for nominal and ordinal data.

Bar Graphs

Which type(s) of frequency distribution graph(s) should be used for data that come from a nominal scale of measurement?

Bar graphs

Which position in a distribution corresponds to a z-score of z = -1.00?

Below the mean by 1 standard deviation

Martha conducts a research study in which she measures how long participants spend trying to solve an impossible problem-solving task before giving up as a measure of perseverance. In this example, perseverance is an example of a(n) __________.

Construct

The amount of time that it takes to solve a problem is an example of a(n) _______ variable.

Continuous

If it is impossible to divide the existing categories of a variable, then it is an example of a(n) ________ variable.

Discrete

__________ is the spread of those scores based on the range of scores and the frequency of each.

Distribution

An independent random sample requires that each individual has an _____ chance of being selected.

Equal

Because probabilities and proportions are _______, a particular portion of the graph corresponds to a particular probability.

Equivalent

Sarah is conducting a research study in which one group of participants consume one cup of coffee, whereas another group of participants consume two cups of coffee. Then, she assesses attention levels of these participants following coffee consumption. This is an example of a(n) _____ research study.

Experimental

For a sample with M = 10 and s = 2, a score of X = 13 would be considered an extreme score, far out in the tail of the distributions.

False

SS/n-1 is the formula for sample variance.

False

The median is considered to be the "balance point" for a distribution because it is the score for which the total distance between scores below the median and the median is identical to the total distance between scores above the median and the median.

False

The sample standard deviation and sample mean are examples of biased statistics.

False

A recent study reported that students who just finished playing a prosocial video game were more likely to help others than students who had just finishing playing a neutral or antisocial game. For this study, the kind of game given to the students was the _______.

Independent Variable

After assessing two individuals' intelligence levels using a questionnaire, a researcher can conclude that Tom's intelligence score is 4 points higher than Bill's. The observations that serve as the basis for this conclusion must come from a(n) _______.

Interval scale of measurement.

Which statement below is true?

It is possible for a distribution of scores to have two modes.

Which statement below regarding populations is true?

It usually is challenging to obtain data from every person in a population

The farther X is away from the u the ______ the z score.

Larger

Consider the two frequency distribution tables below that each pertain to distinct samples. What is the weighted average of these samples when combined? Sample A: X f 6 2 5 0 4 1 3 2 2 4 1 1 Sample B: X f 5 2 4 5 3 1 2 0 1 5

M = 3

What is the mean from the list of scores below: 5 5 5

M = 5

Inferential statistics allow researchers to _____.

Make predictions and generalizations about population.

Which of the following is a critical unique aspect of the experimental method when examining the relationship between two variables?

Manipulation of one variable

Of the following options, which of the following is done first in the order of operations?

Squaring

A z-score establishes a relationship between the score, mean, and ____________.

Standard deviation

Inferential statistics refer to...

Techniques that allow us to study samples and then make generalizations about the populations from which they were selected.

Which of the following is a consequence of increasing variability?

The distance from one core to another tends to increase, and a single score tends to provide a less accurate representation of the entire distribution.

Keith conducts a research study to examine how mental fatigue influences frustration levels. He has one group of participants complete a mentally exhausting problem-solving task for ten minutes, and a second group of participants complete an easy crossword puzzle for ten minutes. Then, he observes participant reactions to being prevented from achieving a desired goal on a second unrelated task as a measure of frustration levels. In this research study, the experimental condition is _____.

The group of participants who complete the mentally exhausting problem-solving task.

For the empirical rule, 95% of scores are within -2SD and +2SD.

True

In a population with a mean of u= 30 and a standard deviation of a o= 5, a score of X = 18 would be an extreme value, far out in the tail of the distribution.

True

Random assignment helps to strengthen casual inferences within an experiment by ruling out potential confounding variables otherwise introduced to an experiment due to individual differences in participants.

True

SS/N is the formula for population variance.

True

SS= S(X-u)2 is the formula for SS population.

True

The median is the value in a distribution of scores that separates the lowest 50% of scores from the highest 50% of scores.

True

What would you use a grouped frequency table?

When you have a wide range of data.

For a population with u = 40 and o = 8, what is the z-score corresponding to X = 34?

z = -0.75

Which z-score value represents the location farthest from the mean?

z = -2.00

Which of the following symbols identifies the population standard deviation?

σ