stats midterm

The following distribution most clearly approximates a

Normal distribution

What is that a Z score 4 score is in the bottom 10%

-1.28

A therapist goes through her records and finds that 200 of her 400 patients showed significant improvement in the mental health over the past year. Hence, the probability of her patients showing significant improvement in mental health is______________.

.50

Below is the probability distribution for the number of times students had to take the same exam before passing it. If a student must pass the exam in two tries or less to pass the class, then what is the probability of passing the class?

.80

Measures of variability can range in value from

0 to positive infinity (+y)

A sampling distribution of the sample mean or variance is

A distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population

A simple frequency distribution

All of these

Which of the following is a type of graphical display use to summarize quantitative continuous data

All of these Histogram Frequency polygon ogive

Grouped data are to ungrouped data as

Continuous is to discrete

The use of tables and graphs to summarize data is an example of

Descriptive statistics

Which type of sampling is most often applied by researchers in the behavioral sciences?

Experimental sampling

As a sample size decreases the standard error also decreases

False

______________ is the variable in an experiment that is manipulated between conditions being observed

Independent variable

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

An animal researcher measures the number of times a rat presses a lever located at the right, center, and left of the cage for a food reward. What scale of measurement is the location of lover pressing?

Nominal

A researcher distributes frequencies frequencies into the following intervals: 1- 10, 11-20, 21-30, 31-40, 41-50 and 50 and above. What is wrong with the frequency distribution?

One interval is an open class

To construct a pie chart, first distribute the data as

Relative percentages

Which of the following measures of attraction is an example of a ratio scale measurement

The physical proximity (in feet or inches) between two romantic partners

A researcher reports that "The average shopper in the sample (n=12) purchased $65 worth of items (m=$65) During a busy shopping day." What mistake was made in this citation?

The sample mean is written using the wrong notation

A binomial probability distribution is the distribution of the random outcomes for a bivariant or dichotomous random variable

True

A main disadvantage of computing a range is that it takes into consideration only two values regardless of the number of scores in the distribution

True

Baye's theorem Is often applied to a variety of conditional probability situations, including those related to statistical inference

True

The sample size is in the denominator of the calculation of a sample mean

True

A therapist has a goal to reduce the mean number of patient symptoms expressed for a particular disorder to two symptoms per day. Following therapy, she determines that the z score for 2 symptoms per day is 0. Assuming the data is normally distributed, did she reach her goal?

Yes, because the Z score of 0 is the average, or mean

A researcher selects a sample of six professors, Six students, and six administrators at a local school and has them rate the effectiveness of an innovative new teaching style. In this example,Is it possible that the weighted mean ratings will equal the arithmetic mean for the entire sample of 18 participants?

Yes, because their are equal number of participants in each sample

Interval scales of measurement

have equidistant scales

Which of the following is not a symbol used with samples?

m.

______________ refer(s) to how the properties of numbers can change with different uses

scales of measurement

A professor grades 120 research papers and reports that the average score was 80%. What do we know about the sum of the differences of these 120 scores from their mean of 80%?

the sum of the differences is equal to zero

The 50th percentile is also called the median quartile

true

A researcher records the following data: 4,4,4,4, an 3. How would you describe the variability of these data?

It is very small (Close to 0) Because scores are approximately the same

Which rule states that when two outcomes are independent, the probability that these outcomes occur together is the product of their individual probabilities?

Multiplicative rule

The distribution of probabilities for each outcome of a random variable that sums to 1.00 is called a

Probability distribution

___________ data describe numeric aspects of phenomena, whereas _________________ data described nonnumeric aspects of data

Quantitative; Qualitative

To determine the interval width, we divided the_____________ by the number of intervals

Real range

Which type of mean is used to describe a portion of individuals in a given population

Sample mean

The following is a simple frequency distribution table. If we convert this frequency distribution to relative percentages,Which of the following gives the corresponding relative percentages in each interval?

20%, 13%,17%,33%,And 17%

A researcher measure the time (in seconds) it takes a sample of 26 participants to respond to a stimulus presented on a computer screen. The standard deviation for response times in 6. In this example, what is the value for SS?

900

Probability allows us to make predictions regarding

All of these Random events Random outcomes Random variables

Descriptive statistics are procedures used to

All of these Summarize, Organize, make sense of scores for observations

A researcher reports that the time (in minutes) it takes children who are "Picky eaters" To finish their vegetables is negatively skewed, with children finishing their vegetables in 4.2 +- 1.0 (M+-SD) min. Based on Chebyshev's Theorem, we can conclude that

At least 89% of children finish their vegetables in 1.2 - 7.2 min.

Adding the same constant to each score in a distribution (Or subtracting the same constant from it) will

Cause the mean to change by that constant

A researcher records the time it takes to complete a memory task in a sample of 25 participants.He finds that the average participant completed the test in 43 seconds.The average time to complete this task is called a(n)

Sample statistics

Which of the following distributions has the largest variability

Scores: 1,3,6,9, and 12

Which of the following is an example of a distribution with NO variability?

Scores: 5,5,5,5,5, and 5

An example of a binomial variable includes

Sex (Male, female)

Which of the following describes a descriptive statistics

Summarize

A percentile point is

The value of a score on a measurement scale below which a specified percentage of scores in a distribution falls

The data should be ungrouped for the following data set: 6,7,7,7,7,7,7,8,8,8,9,9,9,6,6,6,8,7

true

The probability that a participant is married is p(M) = .60. The probability that a participant is married and "In love" is p(MCL) = .46. Thus, The probability that a participant is in love, given that the participant is married, is p=.77

true

A researcher selects a sample of 121 participants from a population with a mean of 32 and a standard deviation of 22. What is the standard error of the mean?

2.0

A counselor records the number of disagreements (per session) among couples during group counseling sessions. If the number of disagreements is distributed normally as 4.4 +- 0.4 (M +- SD) disagreements, when X=0

1.5

A news poll showed about the voters had no preference for either of three candidates. In this example, the probability of a vote for, say, Candidate A equals___________.

1/3

Which of the following probability distributions is accurate

10/80, 23/80, 37/80, 10/80

Suppose that the probability that any child of alcoholic parents becomes alcoholic is P=.16. Assuming independent outcomes, the probability that two children of alcoholic parents will be alcoholic equals _____________.

.03

A researcher records the following scores for an Olympic gymnast following her routine: 9.9, 9.8, 9.6, 9.5, 9.7, 9.1, 8.9, and 9.8. What is the range for the scores?

1.0 (9.9 to 8.9)

As sample size increases, the standard error of the mean

Decreases

The formulas for a population mean and a sample mean are defined using the same notation

False

The sum of the frequencies for a distribution is 100. This means that fewer than 100 persons were counted.

False

a main disadvantage of computing a range is that it is a simple and quick measure of variability

False