STATS exam 2
For a population with u=80 and o=6, what is the z-score corresponding to X=68
-2.00
For a sample of n=20 scores is transformed into z-scores. What is the mean for the set of 20 z-scores?
0
For any distribution, what is the z-score corresponding to the mean?
0
What is the value for E(x-u) for the population
0
What is the value of SS (sum of squared deviations) for the following population? Population: 1,1,1,5
12
A population of N=100 scores has u=30 and o=4. What is the population variance?
16
A population has SS=100 and o^2=4. How many scores are in the population
25
What is the value of SS (sum of squared deviations) for the following sample? Sample: 1,1,1,7
27
A population of scores has u=80. In this population, a score of X=86 corresponds to z=2.00. What is the population standard deviation?
3
In a population with a standard deviation of o=5, a score of X=44 corresponds to a z-score of z=2. Whats is the population mean
34
A sample of n=5 has EX=20 and E^2X=120. For this sample, what is the value of SS?
40
A sample of n=8 scores has SS=50. If these same scores were a population, then the SS value for the population would be
50
Which of the following accurately describes a hypothesis test?
An inferential technique that uses data from a sample to draw inferences about a population
What position in the distribution corresponds to a z-score of z=-1.00
Below the mean by a distance equal to 1 standard deviation
If a hypothesis test leads to rejecting the null hypothesis, it means that the sample failed to provide sufficient evidence to conclude that the treatment has an effect
False
Which of the following accurately describes the critical region?
Outcomes with a very lo probability if the null hypothesis is true
If a hypothesis test produces a z-score in the critical region, what decision should be made?
Reject the null hypothesis
What are the values for SS and variance for the following sample of n=3 scores? Sample 1,4,7
SS=18 and variance=9
What is measured by the numerator of the z-score test statistic
The actual distance between M and u
A researcher selects a sample and administers a treatment to the individuals in the sample. If the sample is used for a hypothesis test, what does the null hypothesis (Ho) say about the treatment?
The treatment has no effect on the scores
If the sample data are in critical region with a=.01, then the sample data would still be in the critical region if a were changed to .05
True
In general, the null hypothesis states that the treatment has no effect on the population mean
True
In most situations, researchers would like the hypothesis test to reject the null hypothesis
True
The critical region for a hypothesis test consists of sample outcomes that are very unlikely to occur if the null hypothesis is true
True
Under what circumstances is a score 15 points above the mean an extreme score relatively far from the mean?
When the population mean is much smaller than 15
A sample has M=72 and s=4. In this sample, what is X value corresponding to z=-2.00
X=64
Which of the following symbols identifies the population standard deviation?
o
A population has u=50. What value of o would make X=55 an extreme value out in the tail of the distribution?
o=1
On an exam with a mean of u=70, you have a score of X=65. Which of the following values for the standard deviation would give you the highest position within the class
o=10
On an exam with u=52, you have a score of X=44. Which value for the standard deviation would give you the highest position in the class distribution?
o=8
A sample of n=9 scores has a variance of s^2=18. If these scores were a population, what value would be obtained for the population variance
o^2=16
Which of the following symbols identifies the sample variance
s^2
A set of 10 scores has SS=90. If the scores are a sample, the sample variance is ______, and if the scores are a population, the population variance is ______.
s^2=10; o^2=9
Which of the following is a consequence of increasing variability?
the distance from one score to another tends to increase, and a single score tends to provide a less accurate representation of the entire distribution
A population has U=50 and o=5. If 10 points were added to every score in the population, what are the new values for the mean and standard deviation
u=60 and o=5
Which of the following z-score values represent the location farthest from the mean?
z=-2.00
For a population with a standard deviation of o=6, what is the z-score corresponding to a score that is 12 points above the mean
z=2
If the sample data are in the critical region with a=.05, then the same sample data would still be in the critical region if a were changed to .01
False
The null hypothesis predicts a specific value for the population mean
False
The null hypothesis states that the sample mean (after treatment) is equal to the original population mean (before treatment)
False
For a hypothesis test evaluating the effect of a treatment on a population mean, what basic assumption is made concerning the treatment effect?
If there is a treatment effect, it will add (or subtract) a constant to each score