Stats test 1
What is the z score for scores in the bottom 5%?
-1.645
A researcher records the following number of birdcalls made during an experimental session with robins: 7.2 ± 0.6 (M±SD). Assuming these data are normally distributed, what is the probability that robins made more than nine birdcalls during this experimental session?
.0013
A researcher measures the following correlation between the number of years of education and life satisfaction: r= +.1. What is the value of the coefficient of determination?
.01
A professor records the grades for his class students. He finds that the probability that a student earns an A is p= .14; earns a B is p= .36; earns a C is p= .32; earns a D is p= .10; and earns an F is p= .08. What is the probability that a student earns a B or better in this class?
.50
The standard normal distribution is normally distributed with a mean of ______ and a variance of ______.
0, 1
A professor finds that the students scored a 76 ± 8 (M±SD) on the final exam. On this exam, a score of 90 is an A. Assuming these data are normally distributed, what is the z score for 90 (the cutoff for an A)?
1.75
A gambler rolls a 3 with one roll of a single fair die. Given that the die was six-sided, what was the probability of rolling a 3 with one roll?
1/6
A researcher measures 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 is 6. In this example, what is the value for SS?
900
A researcher measures the following correlation between cost of produce and number of units sold. Which description best explains the relationship between these two factors? (GRAPH)
Less expensive produce is associated with an increased number of units sold.
A researcher measures the following correlation between cups of coffee consumed daily and daily work schedule. Which description best explains the relationship between these two factors? (GRAPH)
The more a person works, the more coffee he or she tends to drink.
Descriptive statistics are procedures used to
all of the above
By definition, the probability of an outcome or event is
all of these
The sum of the squared deviations of scores from their mean
all of these
The degrees of freedom for the sample variance
are equal to the sample size minus one
A distribution of probabilities for random outcomes of a bivariate or dichotomous random variable is called a
binomial probability distribution
Which of the following is a type of graphical display used to summarize qualitative, discrete data?
both bar and pie chart
Each of the following are interval scale measurements, except
duration of sleep (in hours)
A graphical display for grouped frequency distributions with continuous data is called a
histogram
A researcher measures the time (in seconds) it takes children to complete a basic reading skills task. What type of graphical display would be most appropriate for summarizing the frequency of children falling into different intervals of time
histogram
In the stem-and-leaf display, each number to the right of the vertical line is referred to as a ______; the numbers to the left of the vertical line are called the ______.
leaf, stem
The population mean is symbolized as ______, whereas the sample mean is symbolized as ______.
mue, M
An animal researcher measures the number of times a rat presses a lever located at the right, center, and left of a cage for a food reward. What scale of measurement is the location of the lever pressing?
nominal
The ______ is the percentage of scores with values that fall below a specified score in a distribution
percentile rank
______ data describe numeric aspects of phenomena, whereas ______ data describe nonnumeric aspects of data.
quantitative, qualitative
Which type of mean is used to describe a portion of individuals in a given population?
sample mean
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 s. The average time to complete this task is called a(n)
sample statistic
The correlation coefficient is used to measure the ______ and ______ of the linear relationship between two factors.
strength, direction
Scores far from the mean are located in the ______ of a normal distribution.
tails
Which of the following can be used to estimate the median?
the 50th percentile of cumulative percentage distribution
A researcher records the number of individual instruments identified by students listening to a piece of classical music. He splits the data into quartiles and reports that students correctly identified three instruments at the 25th percentile, five instruments at the 50th percentile, and eight instruments at the 75th percentile. What is the IQR for these data?
the IQR is 5
The most common measure of effect size for the correlation coefficient is called ______.
the coefficient of determination (r^2)
All other things being equal (so assuming that the value of SS never changes), as sample size increases,
the value of sample variance decreases
Suppose you open a new game at the county fair. When patrons win, you pay them $3.00; when patrons lose, they pay you $1.00. If the probability of a patron winning is p= .20, then how much can you expect to win (or lose) in the long run? Hint: You need to compute the expected value of the mean.
win 0.20 cents per play
A researcher records the following data for how participants rated the likability (on a scale from 1 = not liked at all to 7 = very likable) of an individual who blushed after making a mistake: 5, 4, 7, 6, 6, 4, 6, 7, 2, 5, and 6. Is the mode equal to the median in this example?
yes
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?
yes