Psych 200 -Final
what is the z score for scores in the top 2.5%
1.96
what is the value of SS ( sum of squares) for the following population ? 1,1,1,5
12
a researcher records the following times ( in seconds) that it took a group of students to complete an exam: 18+- 2(m+- sd). how log did it take 80% of students to complete the exam?
19.68 minutes
a researcher measures the number of trials it takes two samples of participants to master a new task. in both samples,SS=240. Sample A consisted of 12 participants and Sample B consisted of 18 participants. which sample is associated with the largest variance?
Sample A
a researcher states that a sample of 100 shoppers spend 112+- 40 (m+- sem) dollars on groceries each week. which value is the standard error of the mean
40
a researcher records the following assessment data : 42 +- 6(m+- sd). the researcher only wants to sample participants scoring in the top 20% of this assessment. what is the cutoff score for the top 20% in this example
47.04
for the same distribution shown in question 32, how many people had scores greater than x=14
7
a psychologist treats 16 patients and records the number of sessions required to complete a behavioral therapy treatment for each patient. she computes SS= 800. Assuming the 16 patients constitute all patients under her care (so the population of her patients), what is the standard deviation for these data?
7.1 sessions
a professor records the following final exam scores: 78 +- 7 (M +-sd) students scoring in the top 14% get an A. What is the cutoff score for the top 14% in this example
85.56
a researcher records the sound (in decibels) during a series of lessons taught by a substitute teacher a local elementary school. in his study, he found that the sound was 80+-6 (m +- SD) decibels. assuming the data are normally distributed, which of the following is an appropriate conclusion?
95 % of classes were between 68 and 92 decibels
fill in the missing values for A and B in this frequency distribution table
A =3.2 B=13
a sample size increases, the standard error of the mean
decreases
a researcher records the number of votes for each five candidates running for class president. based on her presentation of the following results, what type of statistics did she use?
descriptive statistics
the use of tables and graphs to summarize data is an example of
descriptive statistics
the sample variance is computed by dividing SS by ___; whereas the population variance is computed by dividing SS by ____
df; N
_______ allows researchers to describe (1) how far scores have shifted in the population, or (2) the percentage of variance that can be explained by a given variable.
effect size
a researcher selects a sample of 25 participants from a population with a mean of 10 and a standard deviation of 5. what is the probability of selecting a sample mean equal to at least 12
equal to the probability of selecting a sample mean that is smaller than 8
a researcher tests whether the dosage level of some drug(low, high) causes significant differences in health. to do this, the researcher randomly assigns rat subjects to receive a low or high dosage of the drug and records health-related measures in both groups. the type of method described is
experimental
three research methods common to research in the behavioral sciences are
experimental, quasi-experimental. and correlational
In a normal distribution , 50% of all data
fall above the mean, fall below the median, fall above or below the mode
internal scales of measurement
have equidistant scales
a graphical display for grouped frequency distributions with continous data is called a
histogram
____________ is the variable in an experiment that is manipulated between conditions being observed
independent variable
procedures that allow researchers to infer or generalize observations made with samples to the larger population from which they were selected best describes
inferential statistics
a researcher measures the body temperature (in degrees Fahrenheit) of participants immediately before and immediately following sleep. Temperature is on what scale of measurement?
interval
a researcher asks adult participants to rank their top five favorite songs from their childhood. based on the scale of measurment described , which measure of central tendency is most appropriate to describe these data?
mode
a professor gives an exam in which the mean score is 78 points. she gives another exam to test whether or not scores change. in this example, the null hypothesis is
mu does not equal 78
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 lever pressing
nominal
an education counselor records the number of high school graduates enrolled in community colleges, four -year colleges, and universities. what scale of measurement is the type of college?
nominal
a researcher distributes frequencies into the following classes: absent, tardy, present. What type of data are distributed?
nominal, qualitative, ungrouped
a researcher selects two samples of 25 participants each. the first sample is from the population where the population mean was 32 and the variance was 8. the second sample is from the population where the population mean was 4 and the variance was 8. which sample will be associated with a larger standard error of the mean?
none, both samples will have the same value for standard error
if the value of the test statistic is in the rejection region, then
p if greater than .05, reject the null hypothesis, test statistics is larger than the critical value
a researcher selects a sample of 36 students from a school population with a mean iq 100 and a standard deviation 12. she found that the mean iq in this sample is 104. assuming she conducts a one-sample z test at a 0.5 level of significance. whats the decision for a two-tailed test?
reject the null hypothesis; iq scores in this sample are significantly higher than those in the population
a characteristic (usually numeric) that describes a sample is called a
sample statistic
researchers measure data in a _____ to learn more about individuals in the larger ____ of interest
sample; population
Based on the effect size conventions, d = 0.18 is a
small effect size
a simple frequency distribution
summarize grouped data, summarize ungrouped data, summarize the frequency of scores in a given category or range
a researcher conducts and experiment to determine whether moderate doses of St. johns wort have any effect on memory for college students. for this study what is the independent variable?
the amount of st. johns wort given to each particiapnt
state the problem with this simple frequency distribution
the class intervals overlap
which of the following best describes a dependent variable
the measured behavior
which proportion is largest in a z distribution?
the proportion of area between z= +1 and z= -1
a researcher identifies college students as a group of interest to test her hypothesis. she then identifies a few local college students and selects a small group of the local college students to observed. in this example , the sample is.
the small group of college students who where observed
a student scores in the 80th percentile on an exam. what does this mean in comparison to all other students
the student scored higher than 80% of all others who took the exam
researchers rarely have access to entire populations. how do researchers resolve this limitation?
they record data from sample of people in the larger population in order to make inferences concerning characteristics in that larger population
recording whom students study with describes____ types of data; whereas recording the number of hours spent studying per week describes _____ types of data
qualitative; quantitative
there key elements of control that allows researchers to draw cause-and-effect conclusion
randomization,manipulation, and comparison/control
to determine the interval width, we divide the ____ by the number of intervals
real range
a professor finds the at the average Sat score among all students attending his college is 1150 +-150. he polls his class of 25 students and finds that the average SAT score is 1200. suppose he computes a one-sample z test at a 0.5 level of significance .what is his decision?
to reject the null hypothesis for a two-tailed test, but to retain the null hypothesis for an upper-tailed test
a researcher obtains z= -6.45. what is the decision for a one-tailed test, upper tail critical, at a .05 level of significance?
to retain the null hypothesis
given the following values: M= 6.0, v =7.6, n=36, sd=6, conduct a one-sample z test at a 0.5 level significance. for one-tailed test, upper-tail critical, what is the decision?
to retain the null hypothesis
a measure of the average squared distance of scores from the mean is called the
variance
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. the mode equal to the median in this example?
yes
a researcher records the following data for the number of dreams recalled during a night of sleep for 10 college students 3,2,4,4,3,1,1,0,2 and 0. is the mean equal to the median in this example?
yes
the unit measurement distributed along the horizontal axis of a standard normal distribution is referred to as a
z-score
the procedure of converting a categorial variable to numeric values, is called
constructing
a researcher determines that students study an average of 80+- 20 (m +-sd) minutes per week. assuming these data are normally distributed, what is the z score for students studying 60 minutes per week?
- 1.0
state the critical value for a t test using the two-tailed test at a .05 level of significance t(20)
+- 2.086
a researcher selects a sample of 25 participants from a population with a mean of 10 and a standard deviation of 5. What is the probability of selecting a sample mean that is at least two standard deviations larger than the population mean?
.0228
what is the typical level f significance for a hypothesis test in behavioral research
.05
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, then what proportion of couples disagree at least 4 times during each counseling session?
.8413
Most behavior is believed to___ a normal distribution
approximate
for the following distribution, what is the highest score
cannot be determined
a method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called
level of significance
the criteria for a decision regarding the value stated in a null hypothesis is set by the
level of significance and p value
a researcher randomly selects a sample of participants from a population with variance of 4. if a researcher selects a sample of 16 participants with a mean of 12, then what is the mean and standard error for the sampling distribution of the mean
mean =12, standard error= 0.5
a researcher believes that increasing attention given to children will improve mean academic performances. therefore, the alternative hypothesis should be:
mean academic performance will increase
