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