Statistics Quiz 1

A class consists of 10 male and 30 female students. A random sample of n = 3 students is selected. If the first two students are both females, what is the probability that the third student is a male?

10/40

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

10/40

A deck of 52 cards contains 12 royalty cards. If you randomly select a card from the deck, what is the probability of obtaining a royalty card?

12/52

After 5 points are subtracted from every score, the sample mean is found to be M= 24. What was the mean for the original sample?

29

A population of N = 8 scores has ΣX = 40. What is the population mean?

5

What is the median for the following set of scores? 1, 2, 6, 11, 17

6

A population of N = 5 scores has ΣX = 40. What is the population mean?

8

A researcher found a positive correlation between the amount of television watched in Fullerton and ice cream sales at Safeway asserted television watching television increased ice cream consumption. His conclusion is

Accurate statistically but inaccurate in conclusion, correlations are not causation

Which of the following actions will always change the value of the mean? a. Changing the value of the score B. Removing a score from the distribution C. All of the choices given here change the mean D. Adding a new score to the distrubution

All of the choices given here change the mean

Which of the following is a requirement for a random sample? A. every individual has a chance of being selected B. The probability cannot change during a series of selection C. The there must be sampling with replacement D. All the answers are relevant for random selection

All the answers are relevant for random selection

Which of the following is not true about a parameter?

Derived from measurements of the individuals in the sample

True or False: Probability predicts the kind of population likely to be obtained

False

To operationalize a construct, you would________?

Identify the set of operations required to measure an external behavior

For an experiment comparing two methods of teaching social skills to autistic children, the independent variable is _______ and the dependent variable is _______.

Independent variable is: teaching methods; Dependent variable is: the social skills that are learned

Which of the following describes a construct?

Internal attributes or characteristics that cannot be directly observed (e.g. Marital Satisfaction)

For a perfectly symmetrical distribution, which relationship is always true?

Mean=Median=mode

A researcher measures eye color for a sample of n=50 people. which measure of central tendency would be appropriate to to summarize the measurements?

Mode

What scale of measurement is being used when a teacher measures the number of correct answers on a quiz for each student?

Ratio

A researcher conducts an experiment to determine whether moderate doses of St. John's Wort have any effect of memory for college students. For this study, what is the independent variable?

The amount of St. John Wort given to each participant

Which of the following is an example of a continuous variable?

The amount of time taken to solve a problem

Which of the following is an example of a discrete variable?

The gender of each student in a psychology class

True or false: Probability is used to determine what sample you will draw from the population when conducting a study?

True

Statistics is used for

organize and summarize information

A researcher uses anonymous survey to investigate the television viewing habits of all American adolescents. The entire group of American adolescents is an example of a ______.

population

Goal of statistical procedures is to:

provide accurate and meaningful interpretation

For a research study comparing attitude scores for males and females, participant gender is an example of what kind of variable?

quasi-independent variable

A researcher uses an anonymous survey to investigate the television-viewing habits of American adolescents. Based on the set of 356 surveys that were completed and returned, the researcher finds that these students spend an average of 3.1 hours each day watching television. For this study, the set of 356 students who returned surveys is an example of a _______.

sample

Although a research study is typically conducted with a relatively small group of participants known as a _________, most researchers hope to generalize their results to a much larger group known as a _________.

sample;population

The average verbal SAT score for the entire class of entering freshmen is 530. However, if you select a sample of 20 freshmen and compute their average verbal SAT score you probably will not get exactly 530. What statistical concept is used to explain the natural difference that exists between a sample mean and the corresponding population mean?

sampling error

A population is the ______ of interest in a particular study

set of all individuals

1. What does Σ stand for?

summation/ summing up all scores

Probability refers to:

the probability of any specific outcome is a fraction or proportion of all possible outcomes.